High Court · Decided 3 May 2011

Public Prosecutor v Mohammad Ashik bin Aris

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[2011] SGHC 111Case no. Criminal Case No. 25 of 2010

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Chan Seng Onn J:
The brief facts
[1] Mohammad Ashik bin Aris (“the accused”) is charged with one count of consumption of Methamphetamine, an offence under s 8(b)(ii) of the Misuse of Drugs Act (“MDA”) and punishable under s 33(1) of the MDA.
[2] At about 10.40am on 22 January 2010, the accused was arrested by a party of Narcotics Officers from the Central Narcotics Bureau (“CNB”) at Kim Tian Hotel. The accused was found in room 202 with an improvised pipe-like instrument (“the pipe”) and 18 packets of crystalline substance (“18 packets”). He was arrested and taken to the Bedok Police Headquarters where three specimens of urine were taken from him. One was subsequently tested to be positive for Amphetamines under an Instant Urine Test conducted at the police station. The remaining two specimens were delivered in a locked metal security box to the Health Sciences Authority (“HSA”) on 25 January 2010. Subsequently, HSA issued two certificates on 28 January 2010, certifying that both urine specimens tested positive for Methamphetamine. On 3 February 2010, the pipe and the substance in the 18 packets were sent to HSA for testing. On 15 April 2010, HSA issued two further certificates certifying that the inside of the pipe was stained with Methamphetamine, and that the crystalline substance in the 18 packets contained Methamphetamine.
[3] At trial, the Prosecution called the director in charge of the laboratory at HSA and all those HSA officers involved in the testing as witnesses to give detailed evidence on the testing methodology, the procedures adopted for the testing of the substances and materials in this case, and their analyses and findings thereto. An expert witness was called to give evidence on the common international practice and to comment on the methods and procedures used by HSA. CNB officers involved in the arrest of the accused, the seizure of evidence from the accused’s room, the recording of the accused’s statements and the collection of urine specimens from the accused were also called to testify.
[4] The Prosecution further adduced three statements made by the accused (“the accused’s statements”) where he admitted that he had the intention of consuming “Ice” and pursuant to that intention, did in fact smoke some substance using the pipe. The first statement was an oral contemporaneous statement made on 22 January 2010 at about 11.00am; the second was a statement made pursuant to s 121 of the Criminal Procedure Code on 22 January at 6.00pm; and the third was a cautioned statement made pursuant to s 122(6) of the Criminal Procedure Code on 22 January 2010 at 9.06pm.
[5] As the Defence did not take the position that the accused had no case to answer, his defence was called. However, the accused chose to remain silent. The Defence called one expert witness to testify on the accused’s behalf.
The section 8 MDA offence
[6] Section 8 of the MDA reads:
[7] Pursuant to s 8(b)(ii), the accused is charged with consumption of the specified controlled drug, “Methamphetamine”. To secure a conviction, the Prosecution must prove beyond reasonable doubt that the accused intended to and did, in fact, consume Methamphetamine. Since the Defence conceded that there was the relevant intention and that the accused had in fact smoked some substance via an improvised pipe (as was admitted by the accused in his voluntary statements), the sole issue before me is whether it was Methamphetamine (and not something else) that the accused had smoked or consumed.
[8] In this regard, I will now focus on three main ways by which the offence of consumption of Methamphetamine may be proven:
(a) Proof by relying solely on the accused’s statements and other circumstantial evidence;
(b) Proof by relying on the evidence as in (a), the HSA certificates for the 18 packets, the pipe stains and the urine tests and the presumption in s 16 of the MDA; and
(c) Proof by relying principally on the two HSA certificates for the urine tests and the presumptions in both ss 16 and 22 of the MDA.
Proof by relying solely on the accused’s statements and other circumstantial evidence
Mens rea
[9] The accused admitted in his statements that at about 12.30am on 22 January 2010, he bought from his usual drug supplier, one “Kopi Kia”, 2.4 grams of what he thought to be “Ice”. According to Assistant Superintendent of Police, Stanley Seah, and Investigation Officer, Staff Sergeant Nur, both of whom have served in CNB for many years, “Ice” is the well known street name amongst drug abusers for the controlled drug Methamphetamine. The Defence does not dispute this. Similarly, Analyst Stephanie Lim Hui Jia (“SL”) from the Illicit Drugs laboratory of HSA also testified that “Ice” is the exclusive street name for Methamphetamine. The accused recalled in his statements that he brought the “Ice” back to his hotel room and repacked it into 24 packets each of 0.1 grams with the help of a digital weighing scale. In between 12.30am and his arrest at about 10.40am, he consumed 6 of these packets using the pipe that had been seized from his room, leaving a remainder of 18 packets. It was further recorded in his statement that the accused identified the crystalline substance in the 18 packets as “Ice”. On his own admission, the accused clearly had the intention to consume Methamphetamine at the time he was using the pipe to smoke the “Ice” taken from the 6 packets.
Actus reus
[10] The dispute in this case centres on the actus reus of consumption. More specifically, since it was not disputed that the accused had smoked something, the question was what he had in fact consumed. The Defence contended that though the accused believed he was consuming “Ice” or Methamphetamine, it was not proven that the substance he had been smoking was in fact Methamphetamine. In other words, the accused could have been mistaken or tricked as to the nature of the substance he had smoked. An analysis of the circumstantial evidence leads me inexorably to reject the Defence’s contention.
[11] The accused admitted in his statements that he was a heavy “Ice” smoker, smoking 5 to 6 packets of “Ice” each day. He admitted that he had, on 5 to 6 previous occasions, bought “Ice” from “Kopi Kia” and repacked it into smaller packets before selling them to his colleagues at the workplace, who imbibed the drug to stay alert while working tedious hours as cleaners. The accused said in his statements, “I did sell to them ‘Ice’ as they need the energy for them to stay awake as smoking ‘Ice’ works for me to stay awake ...”. At a price of $50 for each 0.1 grams packet, the accused made a tidy profit each time.
[12] Certain inferences may already be drawn from the accused’s admissions not relating to the events of 22 January 2010 as recounted above at [11]. First, from the understanding that the accused was selling a substance known as “Ice” to his buyers, the high price charged for each packet containing merely 0.1 grams of that substance and the fact that the buyers were willing to pay those prices, it may be inferred that the substance sold each time was very likely an illicit drug. Second, from his heavy abuse of the drug and his sell-on trade, it is also likely that the “Ice” the accused was consuming and selling was in fact Methamphetamine which provided him and his buyers with the energy to stay awake. One drug abuser might be fooled, but it is very unlikely that the accused and his buyers were all duped as to the true nature of the substance they were abusing. It should be emphasised that the accused did not even suggest in his statements what other substance the so-called “Ice” could have been, if not Methamphetamine. Given the opportunity to testify in court, the accused chose to remain silent. From his refusal to give evidence, I am entitled to draw the adverse inference that the so-called “Ice” he sold prior to his arrest on 22 January 2010 must have been Methamphetamine. I regard this as an inference properly drawn in the light of what the accused had voluntarily stated in his statements.
[13] Next, I refer specifically to the events of 22 January 2010 extracted from the accused’s statements as described above at [9]. According to the accused, he bought “Ice” from “Kopi Kia” as he usually did and smoked 6 out of the 24 repacked packets of “Ice”. The strength of his addiction and the fact that he habitually bought “Ice” from “Kopi Kia” meant it was highly probable that he would have noticed any deviations in the appearance or effects of the “Ice” bought and smoked on 22 January 2010. However, he did not mention in any of his statements that the “Ice” he smoked that morning was any less potent, or that the effects of smoking the “Ice” felt different from normal, or that he had smoked a different substance from that he usually smoked. Indeed, it was his belief as recorded in both his long statement and cautioned statement that he had smoked “Ice” on the morning of his arrest. The necessary implication of his belief is that the substance smoked on 22 January 2010 and on previous occasions were the same substances. Since it is highly likely that the “Ice” smoked on previous occasions was indeed Methamphetamine as I found in the paragraph above, it follows that the “Ice” smoked on 22 January 2010 was also Methamphetamine and not some other type of illicit drug. As the accused refused to testify, I am further drawing an adverse inference that the so called “Ice” from the 6 packets that he smoked on 22 January 2010 was in fact Methamphetamine. It is an inference that I can properly draw in the light of what the accused had disclosed in his statements.
[14] On the totality of the evidence from the accused’s voluntary and unchallenged statements (and without considering any of the HSA certificates), I find that both the mens rea and actus reus of the offence of consumption of Methamphetamine have been proved beyond a reasonable doubt by the Prosecution, and I accordingly find the accused guilty of the charge.
Proof by relying on the evidence as in (a), all the HSA certificates and s 16 of the MDA
[15] It bears noting that all the HSA certificates, considered together with the rebuttable presumption under s 16 of the MDA, buttress the findings that I have reached based on the accused’s statements and other circumstantial evidence. This is even without the Prosecution having the benefit of another rebuttable presumption under s 22 (see [28]) read with s 31(4)(b) (see [73]) of the MDA.
[16] By way of explanation, the HSA analysts certified three “matters” in the various HSA certificates signed by them, namely that:
(a) Methamphetamine was found in both urine specimens taken from the accused;
(b) the inside of the pipe was stained with Methamphetamine; and
(c) the substance in the 18 packets was analysed and identified as Methamphetamine.
The s 16 MDA presumption
[17] Section 16 of the MDA reads as follows:
[18] I note that the Defence did not submit that the HSA certificates were not covered by s 16 MDA or that they were consequently not presumptive proof of the three “matters” listed above at [16]. As s 16 MDA applies to “all matters” stated in an appropriate certificate, the facts stated in the various HSA certificates are presumed to be in existence until the contrary is proved. In other words, if the certificate states, for instance, that upon scientific analysis or examination, (a) what the identity of a particular unknown substance is; or (b) what substance has been found in a specimen, sample or container; or (c) what matter or material has been discovered or detected at a certain location, then that certificate alone, by virtue of s 16, is sufficient proof of that fact until there is credible evidence to prove the contrary on a balance of probabilities that it is not the case. To successfully rebut what is stated in the certificate, the Defence is therefore required to prove the contrary facts. Merely raising theoretical, fanciful or remote possibilities or hypotheticals is hardly sufficient. If the contrary evidence produced by the accused is based on events, occurrences or circumstances that are rather unlikely, improbable or remote, then the accused would not have proved contrary to what is stated in the HSA certificates having regard to the plain language in s 16.
[19] The nature of the s 16 presumption was also recently discussed by the Court of Appeal in Tan Chin Hock v Public Prosecutor [2010] SGCA 49. Chan Sek Keong CJ, delivering the decision of the court, said (at [26]):
[20] Accordingly, until the accused manages to prove otherwise on a balance of probabilities, it is presumed under s 16 that Methamphetamine was in fact found in (a) the accused’s two urine specimens, (b) the stains on the inside of the pipe, and (c) the crystalline substance contained in the 18 packets. I will now deal with the scientific evidence given by the HSA analysts on each of these three “matters” presumed under s 16.
HSA certificate for the pipe stains
[21] Analyst SL from the Illicit Drugs Laboratory in HSA issued a certificate that the pipe was examined and found to be stained with Methamphetamine. Methamphetamine belongs to a class of drugs called “Amphetamines”. Other controlled drugs under this class include Amphetamine, N, a-dimethyl-3,4-(methylenedioxy) phenethylamine (“MDMA”) and a-Methyl-3,4-(methylenedioxy) phenethylamine (“Tenamfetamine”). The street name for the latter two controlled drugs is “ecstasy”.
[22] Burnt stain marks were seen on the pipe, showing that it had been used. A solvent was used to dissolve the stain which remained on the pipe and the solvent was subjected to a GC/MS (Gas Chromatography/ Mass Spectrometer) test. The resultant chromatogram produced by the GC/MS instrument showed three peaks for three different drugs. SL analysed and interpreted the main/highest peak at retention time of 4.26 minutes to be Methamphetamine and concluded that Methamphetamine was the main drug found. Two very much smaller peaks flanked the main peak: one of them at retention time of 3.82 minutes was analysed to be Amphetamine and the other one at retention time of 4.68 minutes was analysed to be N,N- dimethylamphetamine.
[23] SL testified that Amphetamine and N,N-dimethylamphetamine are the pyrolysis products (i.e. the products formed when a substance undergoes heating) of Methamphetamine. This is corroborated by the evidence of the Director of HSA’s Illicit Drugs Laboratory, Dr Yap Tiong Whei Angeline (“Dr Yap”), Analyst Ong Rui Shen (“ORS”) and Analyst Bellene Chung (“BC”). It is also supported by the findings in the article titled “Analysis of pyrolysis products of methamphetamine”. The Defence did not dispute that these are pyrolysis products of Methamphetamine.
HSA certificate for the 18 packets
[24] The 18 packets were sent for analysis by the Illicit Drugs Laboratory. Dr Yap testified that her analysis showed that the crystalline substance in the 18 packets contained only one compound, namely Methamphetamine, at a purity level of 79.7% (which Dr Yap said was very close to the maximum purity for Methamphetamine). There was no Amphetamine found in the 18 packets of crystalline substance. She further testified that the Methamphetamine in the 18 packets was in the d-form of Methamphetamine (the relevance of this will be addressed below at [280] under the heading “Peripheral Scientific Issue 4: d (dextro)- and l (levo)-form of Methamphetamine”). Dr Yap also stated that she had never come across “Ice” exhibits containing Amphetamine.
[25] Dr Yap strongly disagreed that her laboratory would be unable to detect Amphetamine if it were in fact present in the 18 packets of crystalline substance because the operating parameters and conditions of the GC/MS instrument would allow it to pick up a wide spectrum of controlled drugs, including Amphetamine. This was not affected by whether or not an Amphetamine drug standard had been tested on the given day itself. Dr Yap also disagreed that the GC/MS instrument was not able to detect small amounts of Amphetamine and proceeded to show the court that even 0.2 milligrams per ml of Amphetamine would result in a clear peak in the chromatogram generated by the GC/MS instrument.
HSA certificates for the pipe stains and 18 packets not challenged
[26] The Defence did not challenge the accuracy or validity of the facts or matters stated in the HSA certificates with respect to the identity or nature of the controlled substance found in the pipe stains and in the 18 packets. Accordingly it may be inferred that whoever used the pipe (most likely the accused from whom the pipe was seized) had in fact smoked Methamphetamine and not some other type of illicit drug. It is also proved by virtue of the HSA certificate read with s 16 that the crystalline substance in all the 18 packets was in fact Methamphetamine and not some other type of illicit drug.
HSA certificates for the two urine specimens
[27] I will now examine the true nature of the challenge mounted by the Defence in relation to the two HSA certificates for the urine specimens admitted in evidence under s 16. The Defence raised the issue of contamination possibly occurring between the time the accused’s room in the hotel was raided and the time his urine specimens (in two sealed bottles) were sent to HSA for analysis. By way of clarification, the Defence is not saying that an inaccurate or wrong analysis had been made because the urine specimens of the accused, as sent to HSA for analysis, did not in fact contain Methamphetamine. The Defence conceded that HSA had correctly detected the presence and analysed the nature of the controlled drug found in the urine specimens. Instead, what the Defence contended was that the two urine tests were not conducted in compliance with the requirements set out in s 31(4)(b) of the MDA (see [73]).
[28] In this regard, I note as a preliminary observation that non-compliance with s 31(4)(b) is relevant only when the presumption in s 22 is invoked. Section 31(4)(b) has nothing to do with s 16. S 22 states:
[29] As a urine test though not carried out in compliance with the (largely procedural) requirements set out in s 31(4)(b) is, nevertheless, still factually a urine test, it follows that a certificate of the result of that urine test made in relation to a controlled drug or substance, signed by a HSA analyst or such person as appointed by the Minister, is “proof of all matters contained therein” pursuant to s 16 until such time that the contrary is proved. Accordingly, the two certificates for the urine tests, which were signed by the HSA certifying Analysts ORS and BC and carried out in accordance with international standards generally adhered to by other accredited laboratories (even if those standards do not strictly conform with the requirements in s 31(4)(b)), are nevertheless still certificates signed by the HSA analysts for which s 16 remains applicable for the purpose stated therein.
[30] The nature of the presumption in s 16 is very different from that in s 22. The latter goes a further step to presume both the mens rea and the actus reus of consumption while the former only goes so far as to presume what has been stated in the certificate and no more. It may well be that the same facts adduced by the Defence are relevant to rebut both presumptions in ss 16 and 22 but it does not follow that the presumptions in ss 16 and 22 are both identical in their nature and scope, or that s 16 becomes inapplicable for urine test certificates simply because of the existence of s 22 or that s 22 has displaced s 16 specifically for urine tests. In my view, both sections exist separately and operate independently of the other, giving rise to different rebuttable presumptions stated therein in relation to urine tests carried out, provided the pre-requisites in the respective sections are complied with.
[31] For example, if it were true, as was alleged by the Defence, that HSA was given urine specimens to analyse that were pre-contaminated with Methamphetamine, HSA cannot be said to have incorrectly or inaccurately analysed the contaminated specimens if its Analysts were to sign a certificate stating that Methamphetamine (being the contaminant) was in fact found in the urine specimens. HSA has correctly and accurately analysed the contaminants in the specimens. The HSA certificate simply states what substance is found in the urine specimens (which is the “matter(s) contained therein” as referred to in s 16) and does not state why that substance is found there or how that substance came to be in the specimens. From this analysis, it can be seen that the pre-contamination as alleged, while relevant to rebut the presumption in s 22, is irrelevant as far as s 16 is concerned because no rebuttable presumption can possibly arise under s 16 that the Methamphetamine found is the result of excretion from a person who had in fact smoked Methamphetamine since nothing of that sort has been stated by either ORS or BC in their respective HSA certificates.
[32] On the other hand, if s 22 is engaged, then a separate rebuttable presumption arises, that the Methamphetamine found in the accused’s urine specimens was not because of any external pre-contamination, but was the result of excretion of Methamphetamine in the urine discharged by a person, who had earlier smoked or consumed Methamphetamine. In presuming the person “to have consumed that controlled drug in contravention of section 8(b)”, s 22 read together with s 31(4)(b) necessarily presumes also the actus reus of factual consumption and excretion of Methamphetamine by the person providing the urine specimens, whereas s 16, which is independent of s 31(4)(b), does not. In contrast, s 16 alone simply presumes the factual existence of the controlled drug in the urine specimen as stated in the signed certificate of the Analyst until the contrary is proved, and goes no further than that. Even if pre-contamination by a controlled drug is shown to have occurred, the factual existence of that controlled drug in the urine specimen remains valid.
[33] Hence, if pre-contamination is shown on a balance of probabilities to have accounted for all the Methamphetamine in the urine specimen, then that rebuts the presumption in s 22 of the commission of the offence of consumption of Methamphetamine. Therefore, even if s 31(4)(b) is satisfied and the s 22 presumption triggered, the accused must nevertheless be acquitted of the charge of consumption even though the presumption in s 16 itself (i.e. that Methamphetamine was in fact found in the urine specimens sent to HSA for testing) stands unrebutted. In other words, proof that all the Methamphetamine found in the urine specimens was caused by contamination does not rebut the rather “limited” presumption in s 16 that merely presumes the accuracy of the statement in the certificate that Methamphetamine is in the urine. Proof by the Defence of the existence of Methamphetamine contamination of both the urine specimens in fact supports what is presumed in s 16.
[34] I turn now to consider all the evidence in the Prosecution’s case together with the rebuttable presumption in s 16, which, as explained above, stands unrebutted by the contamination allegation. I assume for the moment that s 22 is inapplicable on account of non-compliance with s 31(4)(b). When s 22 is inapplicable, the burden on the accused in order to secure an acquittal is simply to cast a reasonable doubt on the Prosecution’s case that he committed the consumption offence (although Methamphetamine may have been presumed under s 16 to have been found in his urine specimens that were sent to HSA for testing). The line taken by the Defence to cast that reasonable doubt was that though both his urine specimens sent to HSA were correctly analysed to contain Methamphetamine, all the Methamphetamine found in his urine specimens was the result of possible contamination by other sources during the urine collection stage, and not a result of Methamphetamine consumption and excretion through his urine. By way of contrast, if s 22 had been applicable, the Defence would have to go further to establish on a balance of probabilities that the accused had not in fact consumed Methamphetamine, as s 22 presumes the commission of the offence of consumption, until the contrary is proved.
[35] I will now apply the “reasonable doubt” standard since I have assumed that s 22 is inapplicable. The Prosecution has to prove the offence of consumption beyond a reasonable doubt. It is the accused’s evidence that he had repacked the “Ice” bought from “Kopi Kia” into 24 smaller packets from which he smoked 6. The 18 remaining packets were seized by the police and subsequently analysed and certified by HSA analyst, Dr Yap, to contain Methamphetamine. That fact stands unrebutted under s 16 and since the 6 packets of “Ice” admitted to be smoked by the accused came from the same batch of “Ice” as the 18 packets tested by HSA, the common sense conclusion is that the 6 packets of “Ice” contained as much Methamphetamine as the 18 packets were analysed to have. It was also the evidence of the Defence’s expert witness, Dr John Douse (“Dr Douse”) that “Ice” is prepared by allowing a concentrated solution of methamphetamine hydrochloride to form crystals. Since crystallisation occurs uniformly, it is extremely likely that the chemical composition of the same batch of “Ice” is uniform. As the Defence’s submissions did not deal with any of these points, I am not prevented from inferring that the accused did in fact consume Methamphetamine by smoking that substance from those 6 packets with the aid of the pipe over a period of time on the morning of 22 January 2010. The fact that the stains on the inside of the pipe he admitted using to smoke the “Ice” were subsequently analysed to contain Methamphetamine (a) corroborates his admission in his statements that he had believed that he was smoking “Ice” and not some other illicit drug by another street name; and (b) establishes beyond reasonable doubt that his belief was not wrong in fact. It bears repeating here that the HSA certificate for the pipe stains was not challenged and remains unrebutted under s 16.
[36] Finally, the presumption under s 16 in relation to the two HSA certificates for the two urine specimens from the accused also stands unrebutted. Methamphetamine was in fact found in the accused’s two urine specimens sent for analysis. I reiterate that these two certificates never stated why or how Methamphetamine came to be present in the urine specimens, or whether the Methamphetamine found was (a) entirely a contaminant; (b) entirely excreted from the accused’s body; or (c) partly due to contamination and partly excreted. Given what is stated on these two certificates, s 16 cannot and did not presume that the accused had in fact ingested or consumed Methamphetamine.
[37] In the light of the overwhelming evidence of the Prosecution (even without the aid of the presumption in s 22), I now consider if the Defence has succeeded in casting a reasonable doubt on the Prosecution’s case on the basis that the presence of Methamphetamine detected in the urine was due entirely to pre-contamination, thus showing that the accused never consumed any Methamphetamine. Is surfacing a mere possibility of contamination through a variety of sources and pathways during the urine collection process enough to raise a reasonable doubt in the Prosecution’s case that the consumption offence is committed?
[38] In my view, it is insufficient for the accused to show that there was a mere possibility, a reasonable possibility or even a high probability that only part of the Methamphetamine found (at rather high concentration levels) in the two urine specimens came from contamination but the rest of it was due to excretion of the Methamphetamine by the accused in his urine. The charge is still made out as the offence of consumption is independent of whether a small or a large quantity of Methamphetamine has been consumed. For the accused to be acquitted of the charge of consumption, I reiterate that the Defence must raise a reasonable doubt in the Prosecution’s case on the basis that none of the Methamphetamine found by HSA in both urine specimens was the result of excretion and that all of the Methamphetamine came from contamination, giving rise to the inference that the accused never smoked any Methamphetamine. In other words, the reasonable doubt must be in relation to the question whether all and not merely some of the Methamphetamine found at the very high concentration levels of 19,800 ng/ml and 23,300 ng/ml in his two urine specimens had been introduced into his urine specimens as a result of contamination from external sources. Thus, merely showing a possibility that only some Methamphetamine in the urine specimens originated from contamination does not, in my view, take the Defence very far in terms of casting a reasonable doubt on the Prosecution’s case, having regard to the nature of the offence of consumption where the quantity of controlled drug consumed is totally irrelevant for the purpose of proving the offence, so long as the drug (albeit a small amount) is proved to have been consumed.
The details of the Defence’s case on contamination of the urine specimens
[39] Dr Douse explained in his testimony on behalf of the Defence that as the concentration of Methamphetamine in the two bottles of the accused’s urine specimen were “so close”, a “constant drizzle of [drug] particles” into the two urine bottles was needed to produce that result. Dr Douse conceded that it was just “a hypothetical theory” as to how such contamination could arise and he had no scientific proof on this aspect. Pertaining to contamination from the accused’s clothing, Dr Douse referred to an article titled “Results of Methamphetamine-Contaminated Clothing Decontamination in an Experimental Trial”, which concluded that smoking Methamphetamine could result in airborne Methamphetamine particles contaminating the surface of clothing. Pertaining to contamination from the accused’s hands, Dr Douse was unable to say with any certainty how much of the airborne ‘Ice’ particles could have adhered to the accused’s hands.
[40] Based on this, the Defence submitted that a real possibility of contamination exists due to insufficient precautions being taken against contamination during the collection of the accused’s urine specimens at the Bedok Police Station. Hence, the urine test results could not conclusively establish that the accused had consumed Methamphetamine. The Defence argued that the burden on the defence was merely to show the occasion or means of contamination. It was not required to show the degree or amount of contamination. Further, the Defence contended that it was scientifically impossible to prove the extent of contamination for the following reasons:
(a) No steps were taken to guard against any form of contamination at the urine specimen collection stage.
(b) On the facts, the potential for contamination was large as the CNB officer who handled the bulk drugs seizure also conducted the accused’s arrest and urine specimen collection.
(c) No controls were placed within the testing phase at HSA to -show the absence of contamination.
[41] The Defence explored numerous possible sources and pathways of contamination at the trial and in its written submissions, much of which was based on the testimony of Dr Douse. These include:
[42] The numerous possible sources and pathways of contamination alluded to by the Defence related principally to events taking place outside the HSA building (particularly at the Hotel room and Bedok Police Station) and not so much within the HSA itself. Having heard the Prosecution’s evidence, Dr Douse in fact concluded, and quite rightly so, that the urine handling and testing procedures in the Analytical Toxicology Laboratory – Drug Abuse Testing Unit (“DAT laboratory”) met with internationally accepted standards. Since that is the case, it is reasonable to infer that HSA must have put in place sufficient safeguards against contamination within the DAT laboratory. I therefore understand that the Defence is taking issue mainly with contamination occurring during the raid at the Hotel room and the actual urine collection process at the Bedok Police Station, and not contamination occurring within HSA.
Prosecution’s response on the issue of contamination
[43] The Prosecution submitted that the contamination posited by the Defence could be dismissed for the following reasons:
[44] I find that there is no reason to doubt the veracity of Cpl Goh’s evidence.
[45] As the Prosecution has meticulously and accurately set out the evidence of the Prosecution witnesses in relation to the urine collection process, I can do no better than to quote the Prosecution’s submission below:
[46] I accept the evidence of the Prosecution witnesses as set out above, in particular that of Cpl Goh, as proof of what had in fact taken place during the urine collection process. There is no contrary factual evidence before me to contradict Cpl Goh’s evidence or that of the other CNB officers since the accused remained silent.
[47] While the Defence expert had postulated the existence of many sources of contamination and a multitude of pathways by which Methamphetamine contaminants could have gotten into the accused’s urine specimens, I agree with the Prosecution’s submissions that these are merely abstract possibilities (and indeed the Defence expert himself conceded that contamination was a mere “possibility” in the present case).
[48] First, the postulated contamination would not, in my view, be able to account for the presence of Amphetamine in the relatively high quantities found in both the accused’s urine specimens and in approximately the same Amphetamine to Methamphetamine weight ratios. The first bottle of the accused’s urine specimen was analysed to contain 1,476.04 ng/ml of Amphetamine and 19,842.73 ng/ml of Methamphetamine giving a 7.438% weight ratio of Amphetamine to Methamphetamine. The second bottle of the accused’s urine specimen was analysed to contain 1,772.20 ng/ml of Amphetamine and 23,327.80 ng/ml of Methamphetamine giving a 7.597% weight ratio of Amphetamine to Methamphetamine. I note that some deviation in the measured concentrations of the two different drugs in ng/ml of the two urine specimens from the same accused is apparently inevitable when testing for drugs in biological fluids. However, this deviation is in any event within the acceptable variation range of 20%.
[49] It is accepted by Dr Douse and the Prosecution witnesses, namely Ms Shelley Jane Turner (“Ms Turner”), Dr Lui Chi Pang (“Dr Lui”) and a few other HSA Analysts, that Amphetamine is a known metabolite (i.e. the product of metabolism) of the consumption of Methamphetamine and will be discharged in the urine together with the Methamphetamine. Scientific literature also attests to this. As both Methamphetamine and its accompanying metabolite, Amphetamine, are normally discharged in the urine at the same time by the Methamphetamine drug abuser, it would not at all be surprising to find approximately the same weight ratios of the metabolite (i.e. Amphetamine) to the main drug consumed (i.e. Methamphetamine) in both the accused’s urine specimens only if the accused had in fact consumed Methamphetamine earlier. In the present case, the weight ratio of 7.438% for the first urine specimen is in fact nearly identical to the weight ratio of 7.597% established for the second urine specimen. Had it truly been the case that the accused had excreted entirely drug-free urine, and the presence of drug in the urine was wholly due to some possible randomly occurring contamination from fine “Ice” particles falling into the two urine bottles (from the hair, hands, fingernails or clothes), then I would expect (a) the HSA certificates for the urine specimens to show only the presence of Methamphetamine, without any Amphetamine; and (b) the weight ratios of Amphetamine to Methamphetamine for both specimens should also be very close to 0 % since “Ice”, according to Dr Yap, is normally very pure Methamphetamine without any Amphetamine. The Defence did not challenge Dr Yap’s evidence that in all her years of experience, she had not found Amphetamine in its pure form in “Ice” seized and sent to HSA for analysis, save for the general challenge on her laboratory’s ability to detect Amphetamine, which was convincingly resisted by Dr Yap. In fact, there was no Amphetamine found in the 18 packets of “Ice” analysed by HSA, which disproves the Defence’s hypothesis of contamination from the fine particles of pure “Ice” randomly shedding and falling into the urine bottles during the urine collection process.
[50] In my judgment, the joint presence of Methamphetamine and Amphetamine, particularly at about the same weight ratios in the two urine specimens, strongly indicates that both must be attributed to Methamphetamine consumption, and not to some randomly occurring contamination. Random shedding into each bottle of Methamphetamine and Amphetamine particles – assuming Amphetamine was also seized (which was not the case here in any event) and assuming further that there was substantial spillage from the packets of crystalline Amphetamine present in the hotel room, thereby allowing wide spread additional Amphetamine contamination of clothing, body and hair to take place – is not likely to result in almost identical weight ratios in both urine specimens, separately collected. Such random shedding might possibly explain one factual aspect of why there was substantial Amphetamine contamination in the urine collected together with Methamphetamine contamination, but it does not explain the other factual aspect of why both bottles of urine were found to have almost identical weight ratios of Amphetamine to Methamphetamine.
[51] Second, in an attempt to explain why Amphetamine was found in fairly substantial quantities in both urine specimens (which were way above trace or noise levels as could be seen in the chromatograms and the test results), the Defence mooted the next possibility that the accused could have inhaled or consumed Amphetamine instead as a pyrolysis product which led to the presence of Amphetamine in the urine. This also did not help the Defence because the Defence could not identify what other compound could have been burnt (apart from Methamphetamine) that led to Amphetamine as a pyrolysis product. If he was inhaling both Methamphetamine and Amphetamine (as the pyrolysis product of Methamphetamine) at the same time because he was burning the Methamphetamine to consume it, then I do not see how that assists the accused’s defence that he had not been consuming Methamphetamine.
[52] The next theory generated by the Defence attributed the fairly substantial amounts of Amphetamine found together with the Methamphetamine at about the same weight ratios in the urine specimens to the after-effects of smoking the Methamphetamine. The smoking produced Methamphetamine particles and other pyrolysis products in the form of Amphetamine particles in the air at about the same weight ratios, and these two types of particles separately settled onto the clothes, hair, hands or body of the accused and thereafter, found their way into each of the two urine bottles through the small mouth of the bottles (each of just 2.3 cm in diameter), uncapped for just the brief few seconds to collect the urine. This possibility accounted for the dual presence of both controlled drugs in those high concentrations and in approximately the same weight ratios found in both bottles of urine specimens. However, this “smoking” theory of the Defence is a desperate attempt to find some way out to explain why the same weight ratios were found. This “smoking” theory is simply just too improbable for my serious consideration, quite apart from the fact that such a theory premised on smoking Methamphetamine, unless not by the accused, does not seem to me to provide a good defence to the charge.
[53] Third, it is an irresistible deduction from my point of view that the fairly substantial quantity of Amphetamine found in the urine specimens must be the result of the accused’s body metabolising a part of the large amount of Methamphetamine consumed by him prior to his provision of the urine specimens in question, which therefore accounts for their dual presence in those high concentrations at almost identical weight ratios in both urine specimens. There is no other tenable or credible explanation. That he had in fact consumed a substantial amount of Methamphetamine earlier is substantiated by the high concentrations of unmetabolised Methamphetamine found in the two urine samples (in different bottles), which were certified as 19,800 ng/ml and 23,300 ng/ml. These concentration levels are 40 times higher than the cut-off level set internally by HSA of 500ng/ml before HSA is prepared to render a positive report certifying that Methamphetamine is present in the urine specimen. HSA treats results less than 500ng/ml as negative for the presence of Methamphetamine.
[54] Fourth, leaving aside the nearly identical weight ratios found, it is also rather improbable for the Methamphetamine particles to drop into each bottle in such a manner and at such a rate, such that the resultant concentration levels for the Methamphetamine were coincidentally within the normal analytical variation range (in this case 19,800 ng/ml in one bottle and 23,300 ng/ml in the other bottle), unless of course it is assumed that the shedding rate of Methamphetamine particles into both urine bottles was relatively constant and each bottle was opened for about the same amount of time to collect approximately the same quantity of urine from the accused. Dr Douse admitted in cross-examination that the likelihood of roughly an equal amount of “Ice” falling into each of the two urine bottles was statistically “remote”. More importantly, he also conceded, and in my view rightly so, that such contamination (if any) would not in any case have contributed “significantly” to the concentration of Methamphetamine found in the urine. The implication of this concession is that the Methamphetamine concentration found must have come from excretion, which in turn necessarily implicates the accused of having committed the offence of consumption of Methamphetamine.
[55] It only remains for me to conclude that the significant amount of Methamphetamine found in both the urine specimens must be through excretion from the body of the accused and from no other possible sources. I have no reasonable doubt that contamination in the manner as set out by the Defence is a highly unlikely possibility. To confirm that the possibility is indeed very remote, some numeral estimates with certain rational assumptions could be made to find an answer to the question of what extent or amount of contamination through all the various pathways imaginable is needed to account for the actual concentrations of Methamphetamine found in the urine samples. To give a sense of the likelihood of the contamination, Dr Douse himself volunteered some calculations and testified as follows:
[56] I checked Dr Douse’s calculations and found them to be correct based on the following assumptions: that the density of the crystalline Methamphetamine is the same as that of water at 1 milligram or 1000 micrograms per mm3 and that each particle is a perfect sphere with the different diameters as indicated. I can accept that these are not unreasonable assumptions for the purpose of the calculations performed by Dr Douse. In summary, Dr Douse’s calculations show that 5 spherical Methamphetamine particles, each of 0.5 mm in diameter, falling into the urine bottle containing 15 ml or 15 cc of pure or drug-free urine will be sufficient to contaminate the urine to a concentration level of 20,000 ng/ml of Methamphetamine. If the spherical Methamphetamine particles were smaller at 0.05 mm in diameter, then 4,600 particles will be needed to give a contamination level of 20,000 ng/ml. If the contamination is found at the lowest cut-off threshold of 500ng/ml needed for the certification of the presence of Methamphetamine, then a correspondingly lower number of particles is needed to achieve that lower level of contamination (i.e.115 spherical Methamphetamine particles of 0.05 mm in diameter are required to give a contamination level of 500 ng/ml).
[57] However, these calculations merely show the amount of particles needed to be shed into each bottle to achieve the concentration levels found. In my view, they mask the fact that the large quantities of Methamphetamine particles (i.e. 4,600 spherical Methamphetamine particles of 0.05mm diameter or 5 spherical Methamphetamine particles of 0.5 mm diameter) have to enter each bottle within a very short space of time, indicating that the rate of shedding must be very high. It takes perhaps less than 5 seconds to fill a bottle with 15 ml of urine and the window period for the shedding of Methamphetamine into the bottles is not much longer than the time spent urinating into each bottle. The more important question that springs immediately to mind is what total quantity or weight of Methamphetamine the accused’s body, hand, hair and clothes must be carrying for that rate of continuous shedding to last throughout the long hours that passed between his arrest and his urine collection. Shedding could not possibly take place only when the accused was urinating and not at other times. Hence, shedding must necessarily be continuous, and the rate of shedding must obviously decrease with time.
[58] The simple calculation below will show that it is highly improbable to sustain the high rate of shedding postulated by Dr Douse which is necessary to attain the contamination concentration levels matching that found in the urine specimens, which therefore assures me that the contamination from shedding (as a cause for the high concentration of Methamphetamine found in both urine specimens) is indeed very remote, if not, impossible.
[59] It was Dr Douse’s evidence that a transfer of 0.3 mg (equivalent of 300,000 ng) of Methamphetamine into 15 ml of urine specimen (about half the size of the urine specimen bottle) was required to obtain a Methamphetamine concentration of 20,000 ng/ml. I agree with that as it is mathematically correct. Assuming a constant rate of shedding or a constant drizzle of Methamphetamine particles (as Dr Douse himself had postulated), and a very generous time window of 15 seconds to provide each urine specimen, that means 0.3 mg of Methamphetamine particles must fall continuously from a “small area” of the accused’s clothes, hair and body that is immediately above and near the vicinity of the mouth of the bottle every 15 seconds during the urine collection process. I am also very generous to assume for the moment that all the 0.3 mg of Methamphetamine particles that were shedding from that “small area” during that 15 seconds somehow managed to find their way into the bottle through its small opening, with no wastage of particles falling to the floor (which in my view is also highly unlikely). Since the accused was arrested at about 10.40am and the urine specimens were provided shortly after 1.20pm on the same day, the accused had been shedding particles over (at least) a continuous period of 2 hours and 40 minutes. A rate of shedding of 1.2 mg every minute (0.3mg/15 sec) over the elapsed period of 160 minutes (2 hours 40 minutes) works out to a total shedding of 192 mg of particles. This means that 0.192 grams of Methamphetamine, or almost two packets of the ”Ice” (as each packet of “Ice” packed by the accused contained 0.1 gms of Methamphetamine assuming the “Ice” to be pure Methamphetamine) were condensed on that “small area” of the accused’s body, hand, hair and clothes. As Dr Douse accepted, that was not remotely possible.
[60] If one adopts a more realistic assumption that the collection of each 15 ml urine (approximately half a bottle of urine) would not take as long as 15 seconds, and is more likely to be in the order of 5 seconds, then that “small area” of body, hand, hair and clothing of the accused would be carrying not two but six packets of drugs. If one takes further account of the fact that it is unlikely for the deposit of Methamphetamine particles to be solely concentrated on the “small area” immediately above where the urine bottle will be held during urine collection, and that it is far more likely for the Methamphetamine particles to be distributed also randomly over other parts of the accused’s body, hair and clothes, and if we conservatively assume the contaminated area to be three times larger than the “small area”, then the total quantity of Methamphetamine particles clinging onto the entire area of the clothing, head and body of the accused will amount to a total of 18 packets of drugs. If one further considers that the rate of shedding would not have been uniform but would have been much higher initially at the time of the accused’s arrest and thereafter taper off gradually over 160 minutes till the time of urine specimen collection, then the 18 packets worth of Methamphetamine contaminant particles deposited on the accused’s clothing, hair and body would in fact be a serious underestimation. This simple rough analysis shows that the contamination hypothesis of the Defence is entering the realm of science fiction. Basically, all the Methamphetamine in the 18 packets would have to be clinging to his clothes, hair and body as contaminants to be gradually shed over 160 minutes to achieve the concentration levels found in the urine specimens. If that were the case, we will not be finding 18 packets of Methamphetamine each containing 0.1 grams of the drug still lying around to be seized by the CNB officers at the time of the arrest. With the equivalent of 18 packets of Methamphetamine on his clothing, hair and body, Cpl Goh would have to be blind not to have immediately noticed such a large quantity of crystalline substance on the accused’s clothes, hair and body. In fact, Cpl Goh’s evidence was that he had done a body search on the accused at the time of his arrest and he did not notice any part of the accused’s body coated with powdery or crystalline substances. Cpl Goh also did not see any tears on the 18 packets of crystalline substances seized from a table in the hotel room, which would then not give any cause for concern that a large part of the crystalline substance from these packets might somehow have spilled out and found its way onto the accused’s body, hair or clothing. Gpl Goh testified that he did not use his bare hands as he wore gloves to handle the seized exhibits. This also minimises the likelihood of contamination stemming from Cpl Goh’s bare hands. I have no reason to doubt Cpl Goh’s evidence.
[61] The discussion above demonstrates quite convincingly that it is rather fanciful, if not incredible, to hypothesise that all or even a significant part of the Methamphetamine found in the two urine samples came exclusively from contamination.
[62] The following dicta of Denning J in Miller v Minister of Pensions [1947] 2 All ER 372 at 373, which has been accepted as correctly stating the law in Singapore (see Took Leng How v PP [2006] 2 SLR(R) 70 at [28]; see also Jagatheesan s/o Krishnasamy v PP [2006] 4 SLR(R) 45 at [49]), is apposite here:
[63] The Court of Appeal in Took Leng How also endorsed the following statement of leading academic Tan Yock Lin at [29]:
[64] While it is of course possible that there can be contamination, however on the facts of the present case it was most improbable that contamination accounted for the high concentrations of Methamphetamine found in both urine specimens. The Defence’s theory of contamination remains as a “mere doubt” that cannot be “concretely articulated in relation to the evidence in the case” and I reject it outright. The Defence has not succeeded in casting a reasonable doubt on the Prosecution’s case that the accused had consumed Methamphetamine and then discharged it subsequently (together with the metabolite, Amphetamine) via his urine into the urine bottles that were sent to HSA for analysis.
[65] On the totality of evidence, I therefore find that it was the accused’s consumption of Methamphetamine that accounted for the bulk of (if not all) the Methamphetamine and Amphetamine in both his urine specimens. Even if a small proportion of the Methamphetamine and/or Amphetamine in his urine had been due to the consumption of pyrolysis products but a much larger portion came from contamination, this still does not affect the accused’s liability for the offence as he would still have consumed Methamphetamine and committed the offence.
Lack of safeguards against contamination during the urine specimen collection
[66] The Defence zealously submitted that no effective steps were in place to guard against contamination during the urine specimen collection, especially when bulk drugs (as in this case) were seized and the associated risk of contamination was necessarily greater. As such, this gives rise to the probability that some of the means of contamination had indeed brought about contamination, though the amount of contamination was not ascertainable.
[67] Dr. Douse suggested that having controls to prevent contamination was a crucial procedure to provide some measure of certainty to the court of the absence of contamination. He said:
[68] According to Dr. Douse, forensic laboratories in the United Kingdom make it a point to ensure that a different police officer conducts the arrest and supervision of urine collection so that the potential for cross-contamination is negligible. However, Dr Douse was extremely forthright to say that it was implausible in this case for the contamination to have contributed significantly to the high concentration of Methamphetamine detected in the urine specimens, and I have to agree with him. It is true that the precise extent of contamination, if any, in this case is an area of some uncertainty, but on the facts of this case, I am fairly certain that there is only a very remote possibility that contamination alone can explain such high concentration levels of Methamphetamine found. As the possibility of contamination can never be entirely discounted, I can accept that there is always room for improving the safeguards against the possibility of contamination during the urine collection process. For example, the following processes could be implemented:
[70] All said and done, the Defence has not succeeded in casting a reasonable doubt on the Prosecution’s case proving that the accused had in fact consumed Methamphetamine, and consequently, that he had committed the offence as charged. In my view, the Prosecution’s evidence, coupled with adverse inferences drawn by me and the unrebutted presumptions available to the Prosecution under s 16 arising from the four HSA certificates, is in fact overwhelming. The Prosecution need not rely on the s 22 presumption at all to prove the charge against the accused beyond a reasonable doubt. I have no hesitation whatsoever in finding the accused guilty as charged.
Proof by relying on the two HSA certificates for the urine tests plus the presumptions under ss 16 and 22
[71] The evidence considered so far amply justifies convicting the accused. But consumption of Methamphetamine can also be independently proven by utilising s 22 of the MDA, which presumes both the mens rea and actus reus of consumption (Vadugaiah Mahendran v PP [1996] 1 SLR 289).
[72] For the purpose of the following analysis, I will assume that the main evidence available to the Prosecution are the two HSA certificates stating that the accused’s urine specimens contained Methamphetamine. I further assume that no drug exhibits or drug paraphernalia were seized from the accused and that he did not make any admissions in his statements to the CNB officers. The Defence remains unchanged in that there is the possibility of contamination from various sources and pathways, and that the s 22 presumption (see above at [28]) is inapplicable because the necessary requirements in s 31(4)(b) (see below at [73]) are not satisfied. I will now consider whether the Prosecution is able to prove the offence of consumption under these artificially modified factual circumstances.
[73] The operation of the s 22 presumption depends on fulfilment of the requirements set out in s 31(4)(b) in relation to urine tests. Section 31(4)(b) states:
[74] In order to determine whether the charge of consumption against the accused is proved under the assumed circumstances, four separate questions must be addressed:
[75] With respect to the above, the Defence asserted that:
[76] During the trial, references were made to dicta in Lim Boon Keong v Public Prosecutor [2010] 4 SLR 451 (“Lim Boon Keong”) where Steven Chong J made several observations on the interpretation of s 31(4)(b), particularly on whether the standard procedures adopted by HSA for the urine tests had satisfied the legal requirements set out. Much of defence counsel’s cross-examination was premised on the learned judge’s observations in Lim Boon Keong. Although I am not bound by those observations, their persuasiveness compels me to record in some detail the reasons for my conclusions here, which in some aspects differ from the learned judge, who was, unfortunately, not given the benefit of all the evidence that was before me.
The Prosecution’s evidence
[77] Voluminous evidence was led during the trial on the HSA standard operating procedures, the administrative tasks at HSA prior to the urine tests, the urine test protocols themselves, the maintenance and operation of the various test instruments, and more importantly, the internal controls, supervisory mechanisms and various checks carried out by the certifying Analysts through the analysis and interpretation of data and chromatograms produced by the test instruments used at the DAT laboratory to analyse the urine specimens. I turn now to the first question in the analytical framework that I have set out in [74].
[78] It is necessary to trace how urine specimens contained in urine bottles are first received at HSA, what administrative steps follow to process the urine bottles, how small quantities of urine samples are first extracted from the urine specimens in the urine bottles and placed into test tubes in preparation for the different tests, how the actual urine samples are physically and chemically treated thereafter, what quality control samples and calibration standards are introduced, how the various tests are subsequently conducted in the laboratory to screen and analyse the urine samples using the different laboratory equipment and test instruments, and what analytical work for the urine tests are performed by the certifying Analysts before they issue the certificates.
[79] I am particularly grateful to the Prosecution for carefully setting out this part of the largely uncontroversial evidence in a clear and methodical fashion in their written submissions, which I shall conveniently adopt in full with only minor amendments. With this detailed evidence, there can then be a fuller appreciation of:
[80] Without the detailed evidence, it would be much more difficult to identify factually where the precise commencement point for the “urine test” should be and why it should be so, and whether in fact “different” persons had been engaged to perform the “urine test” from the time it commenced, and whether the certifying Analyst can then be said to have “conducted” that “urine test” within the meaning of s 31(4)(b).
(1) Submission of the accused’s urine specimens to HSA
[81] On 25 January 2010, thirty eight bottles of urine specimens were transported in a locked security box to the Analytical Toxicology Laboratory (“ATL”) of HSA by police officer Staff Sergeant Sanjit Singh Bal s/o Manjit Singh (“SSgt Singh”). Of the thirty eight bottles, two bottles contained the accused’s urine specimens. The Corporate Support Officer (“CSO”) of the ATL, Siti Norhayati B M Raji (“SN”) unlocked the locked metal security box with a key kept at the registration counter. In his presence, another CSO Kamisah Bte Amat (“KBA”) retrieved the first bottle of the accused’s urine specimen and SN retrieved the second bottle of the accused’s urine specimen. Both of them checked the details on the CNB Urine Barcode label against the CNB Request Form for the accused before accepting the two bottles of the accused’s urine specimens together with the other urine bottles containing the urine specimens of other accused persons.
(2) The handling of urine specimens by HSA
[82] Dr Lui Chi Pang (“Dr Lui”), the Director of the Illicit Drugs and Toxicology Division of HSA and the Director of the ATL laboratory (in which one of the units is the DAT laboratory) since June 2003, gave detailed evidence on how HSA handles the urine specimens submitted to it, from the point of receipt up until the point of time when the certificates under s 16 of the MDA are issued. In short, this entire process will be referred to as “the handling” of the urine specimens.
[83] Notably, Dr Lui produced a detailed report, which gives a step-by-step description of the various steps carried out by the various DAT laboratory personnel during the handling of the urine specimens. The detailed report also gives a complete picture of the DAT laboratory’s procedures in handling urine specimens. According to Dr Lui, such detailed evidence has never been led in any previous cases of drug consumption, including the recent case of Lim Boon Keong v PP [2010] 4 SLR 451 (“Lim Boon Keong”).
(3) The DAT laboratory’s protocols
[84] Dr Lui’s evidence is that DAT laboratory’s protocol for the testing of Amphetamines is contained in the DAT Laboratory Manual (“the Laboratory Manual”). The purpose of the Laboratory Manual is to provide a standard operating procedure for laboratory officers and analysts to follow strictly in the course of their work.
[85] Dr Lui stated that the procedures in the Laboratory Manual are based on an internationally accepted methodology, viz, the methodology contained in the United Nations Manual, “Recommended Methods for the Detection and Assay of Heroin, Cannabinoids, Cocaine, Amphetamine, Methamphetamine, and Ring-Substituted Amphetamine Derivatives in Biological Specimens” (“the UN Manual”). He stated that the DAT laboratory’s protocol for the testing of Amphetamines conforms to the UN Manual in the following respects:
[86] Dr Lui stated that apart from the testing protocol, the procedures for other aspects of the handling of urine specimens (e.g., screening, sampling) are also found in the DAT Laboratory Manual (Urine Specimen Handling) while the general principles of laboratory management followed by the DAT laboratory are found in the DAT Laboratory Manual (Laboratory Management). The substance of these two manuals is reflected in his report.
(4) Division of labour between analysts and laboratory officers
[87] Crucially, the UN Manual does not stipulate which laboratory personnel should handle particular parts of the handling of urine specimens. Instead, reference is made to the need for “adequately trained and skilled personnel”, “an authorised person” and “properly trained and skilled personnel”.
[88] In the DAT laboratory, the two main categories of laboratory personnel are “Laboratory Officers” and “Analysts”. Laboratory Officers provide technical support to the Analysts. Dr Lui testified that far as he was aware from the archived manuals and records of the DAT laboratory, there were always these two categories of laboratory personnel involved in the handling of the urine specimens. Dr Lui himself had worked in the DAT laboratory of the Department of Scientific Services, as HSA was then known, since 1994 before being appointed as head of the DAT laboratory in 2003. Analysts were previously known as “Government Chemists” (as far as from 1977) and thereafter “Scientific Officers”, before the nomenclature was changed to “Analyst” in 2001 when HSA was formed.
[89] The criterion for appointment as an Analyst in HSA is a 2nd upper honours degree in Chemistry or a related field. On the other hand, Laboratory Officers can be graduates with 2nd lower honours degrees, graduates without an honours degree or diploma holders.
[90] Dr Lui testified that he allocated certain tasks to the Analysts and others to the Laboratory Officers on the following basis:
[91] Dr Lui elaborated that the general division of labour at the material time (when the accused’s specimens were sent to the DAT laboratory) was as follows:
[92] According to Dr Lui, it would not be the best way of managing the DAT laboratory to have Analysts perform all the tasks carried out by the Laboratory Officers because those tasks can be performed by persons without university degrees. The Laboratory Officers are given training to perform sample preparation and to operate the instruments. They have to pass annual proficiency tests to demonstrate their competency. All instructions relating to the various tests are readily available and found in the Laboratory Manual. A duty Analyst is nevertheless always available to answer any queries that a Laboratory Officer might have. Any anomaly or error observed during the urine test by the Laboratory Officer will be brought to the duty Analyst’s attention.
[93] Dr Lui also testified that the division of labour between Laboratory Officers and Analysts is not unique to the DAT laboratory alone. Other laboratories that use laboratory technicians or technical support in the handling of urine specimens for drug abuse testing include the Hong Kong Government Laboratory and the US Navy Drug Screening Laboratory.
(5) Typical workflow – general
[94] In his report, Dr Lui tabulated the typical workflow applicable to the handling and testing of urine specimens (of the accused) in the DAT laboratory. The table is as follows:
[95] Exhibit P67 attached to this judgment at Annex A identifies the different laboratory personnel at HSA, who performed the various tasks as described above in “Table 1 – A typical workflow of urine testing for Amphetamines” in relation to the accused’s two urine specimens that were sent to HSA for testing.
[96] Two aspects of the typical workflow may be noted. First, at the stage of “Sampling” under “Sample preparation” (“the sampling stage”), the first bottle of urine specimen of the accused was handled by a different person and separately from the second bottle of urine specimen from the same accused. This was keeping with the spirit of independence in s 31(4)(b), which requires that the testing of two specimens of the accused’s urine be done by different analysts. Dr Lui said that it was not necessary for administrative purposes to have different personnel at an even earlier stage, such as the specimen unsealing stage and especially not at the “Screening” stage (“the screening stage”) as only one of the bottles of the accused person’s urine specimen is screened. In the course of cross-examination, Dr Lui explained his reasons:
[97] Dr Lui also testified that use of the same personnel to carry out the “Checked by” function (see Table 1 at [94]) at various stages (e.g., Laboratory Officer B checked the receiving of both bottles of urine specimen) did not compromise the independence of the handling of the urine specimens. For instance, at the “GC/MS instrumental testing” stage, when the same Laboratory Officer checked the GC/MS test queue sequence for both the first and second set, this did not affect independence as she was not carrying out any test and was only checking the sequence. This Laboratory Officer was neither the one who placed the GC/MS glass vial into the instrument nor the one who set up the GC/MS test sequence using the computer. The actual sample preparation, placement of the GC/MS glass vials and keying of the particulars into the computer attached to the GC/MS instrument were done by different Laboratory Officers for each set. (At this juncture, it must be noted that the term “Checked by” used in the typical workflow has to be read in context of the Laboratory Manual to give meaning to the term. For instance, at the “GC/MS instrumental test” stage, when it is said that the certifying Analyst C carried out the “Checked by” function, it means Analyst C checked the results of the GC/MS chromatograms after they had been printed out by the GC/MS instrument and not in real time.)

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Public Prosecutor v Mohammad Ashik bin Aris

Laws this judgment relies on

Grounds of decision

The brief facts

The section 8 MDA offence

Proof by relying solely on the accused’s statements and other circumstantial evidence

Mens rea

Actus reus

Proof by relying on the evidence as in (a), all the HSA certificates and s 16 of the MDA

The s 16 MDA presumption

HSA certificate for the pipe stains

HSA certificate for the 18 packets

HSA certificates for the pipe stains and 18 packets not challenged

HSA certificates for the two urine specimens

The details of the Defence’s case on contamination of the urine specimens

Prosecution’s response on the issue of contamination

Lack of safeguards against contamination during the urine specimen collection

Proof by relying on the two HSA certificates for the urine tests plus the presumptions under ss 16 and 22

The Prosecution’s evidence

(1) Submission of the accused’s urine specimens to HSA

(2) The handling of urine specimens by HSA

(3) The DAT laboratory’s protocols

(4) Division of labour between analysts and laboratory officers

(5) Typical workflow – general