Public Prosecutor v Ang Soon Huat

JurisdictionSingapore
Judgment Date01 October 1990
Date01 October 1990
Docket NumberCriminal Case No 34 of 1987
CourtHigh Court (Singapore)
Public Prosecutor
Plaintiff
and
Ang Soon Huat
Defendant

[1990] SGHC 121

Chan Sek Keong J

and

F A Chua J

Criminal Case No 34 of 1987

High Court

Constitutional Law–Equal protection of the law–Methods applied in measuring weight of drugs–Whether Prosecution allowed to justify measurement in this case by using method of computation other than the one normally used in all drug trafficking cases–Article 12 (1) Constitution of the Republic of Singapore (1985 Rev Ed)–Criminal Law–Statutory offences–Misuse of Drugs Act–Trafficking in controlled drugs–Weight of diamorphine–Process of calculation–Whether laboratory procedures sufficiently rigorous in terms of prevailing standards–Whether analysed samples representative of the entire exhibit–Sections 5 (a), 16 Misuse of Drugs Act (Cap 185, 1985 Rev Ed)–Evidence–Admissibility of evidence–Computer printouts of results of scientific tests–Computers not only recording but processing and calculating information fed into them–Whether constituting real evidence or hearsay evidence–Sections 35, 67 Evidence Act (Cap 97, 1985 Rev Ed)–Evidence–Proof of evidence–Doubt existing whether accused committed offence in a lower or higher degree of seriousness–Whether court should make finding in lower degree–Evidence–Witnesses–Expert evidence–Conflict of expert evidence on scientific matters–Defence criticism of Prosecution expert evidence appearing to be justified–Prosecution failing to produce additional expert evidence–Whether court should conclude that reasonable doubt thrown on validity of Prosecution evidence

The accused was charged with trafficking in diamorphine. A successful arrangement was made for a Central Narcotics Bureau officer to buy about a quarter pound of heroin from the accused and it led to the arrest of the accused with a plastic packet containing a pinkish granular substance. This plastic packet was sent to the Department of Scientific Services (“DSS”), the contents of which (“the exhibit”) were analysed and found to contain not less than 18.61g of diamorphine. For this purpose, three samples were taken from the exhibit. The accused called an expert witness to challenge the weight of the diamorphine in the exhibit, a figure calculated and certified by one Dr Chow Shui Tse (“Dr Chow”). The Defence also made the following arguments: (a) if the DSS's rules and formulae used to compute the 'official' weight of the heroin (as was the case in all other cases of trafficking) were found to be incorrect, the Prosecution was not entitled to justify their measurement on some other method of computation as this would deprive him of his constitutional right to equal protection of the law under Art 12 (1) of the Constitution of the Republic of Singapore (1985 Rev Ed); and (b) the computer printouts of the results of the scientific tests carried out were inadmissible because the conditions in s 35 of the Evidence Act (Cap 97, 1985 Rev Ed) had not been complied with.

Held, convicting the accused of trafficking in not less than 10g and not more than 15g of heroin:

(1) The equal protection clause is contravened only if there is deliberate and arbitrary discrimination against a particular person. Arbitrariness implies the lack of any rationality. This could not describe the attempts of the Prosecution to justify its measurement on some other basis which was not scientifically or logically invalid. There was no constitutional protection against the application of correct scientific formulas and facts to any prosecution of accused persons: at [23].

(2) The computer printouts of the results of the scientific tests were real evidence and not hearsay evidence. The computers in the scientific instruments not only recorded but also processed and calculated the information fed into them and oral evidence had been given in regard to those matters. Section 35 of the Evidence Act applied only if the computer printouts were put in as evidence of the facts stated therein without more: at [27].

(3) For the purpose of evaluating a scientific experiment or a laboratory analysis, the written record was absolutely vital. In the absence of a laboratory manual and/or notes of the preparatory steps the recorded entries in the laboratory instrument proved nothing about accuracy of conditions or of performance. There was also a lack of consistency in the use of decimal points to calculate different factors that went into the calculation of the final weight. The laboratory procedures prevailing at the time the tests were done on the exhibit was not sufficiently rigorous in terms of the standards required of scientific analysis of drugs: at [35] and [38].

(4) The exhibit had not been tested for homogeneity and there was a difference of 20% between the lowest and highest data from the three samples. The Prosecution had not proved beyond a reasonable doubt that the weight of the heroin as calculated from the analysis of the three samples was representative of the remaining 99.5% of the exhibit: at [46].

(5) Dr Chow, by simply giving a certain allowance to make sure any errors in his method was compensated for, appeared to short cut the many steps which the accused's expert maintained was required of a properly conducted laboratory analysis of drugs and the criticism of this aspect of Dr Chow's methodology appeared to be justified. Where there was a dispute between the experts for the Prosecution and the Defence as to the proper method of calculating certain scientific values, it was incumbent on the Prosecution to produce additional expert evidence. Otherwise, the court could only come to one conclusion that the Defence had thrown a reasonable doubt on the validity of the Prosecution evidence on the point: at [48].

(6) Having failed to prove that the exhibit contained 18.61 g of heroin, the Prosecution argued that it was impossible for Dr Chow to have made an error of more than 3.61g (24.07% of 15) and there was no reasonable doubt to support a charge that the amount was more than 15g, as opposed to a lower charge of more than 10g but less than 15g. However there was no evidence as to the probabilities of Dr Chow making such an error and therefore there was no fact on which the court could draw such an inference except by inferring that there was no probability of Dr Chow making an error of 24.07%, which the court was not prepared to do. Where the court was, on the evidence, left in doubt as to whether the accused had committed an offence in a lower or a higher degree of seriousness, the court should make a finding in the lower degree, particularly where a finding in a higher degree would give rise to a mandatory sentence of death: at [57] to [60].

Aw Kew Lim v PP [1987] SLR (R) 443; [1987] SLR 410 (distd)

Castle v Cross [1984] 1 WLR 1372; [1985] 1 All ER 87 (folld)

Garner v DPP [1990] 90 Cr App R 178 (folld)

Haw Tua Tau v PP [1981-1982] SLR (R) 133; [1980-1981] SLR 73 (folld)

Howe Yoon Chong v Chief Assessor [1990] 1 SLR (R) 78; [1990] SLR 4 (folld)

J S (A Minor), In re [1981] Fam 22; [1980] 1 All ER 1061 (folld)

Miller v Minister of Pensions [1947] 2 All ER 372 (folld)

Press Trust of India v Union of IndiaAIR 1974 SC 1044 (refd)

R v Van Beelan [1973] 4 SASR 353 (folld)

R v Wood (1972) 76 Cr App R 23 (folld)

Yick Wo v Hopkins (1886) 118 US 357 (refd)

Constitution of the Republic of Singapore (1985Rev Ed)Art 12 (1) (consd)

Evidence Act (Cap 97,1985Rev Ed)ss 35, 67 (consd)

Misuse of Drugs Act (Cap 185, 1985Rev Ed)ss 5 (a), 16 (consd);s 33

Chan Seng Onn (Deputy Public Prosecutor) for the Public Prosecutor

Kan Ting Chiu (Low Yeap & Co) for the accused.

Judgment reserved.

Chan Sek Keong J

(delivering the judgment of the court):

1 The accused, Ang Soon Huat, was charged as follows:

You, Ang Soon Huat, on or about 29 September 1986 between 10.50pm and 11.15pm, in Singapore, did traffic in a controlled drug specified in Class 'A' of the First Schedule to the Misuse of Drugs Act (Cap 185), to wit, by transporting one plastic packet of drug containing not less than 18.77g of diamorphine in motor car JBJ 3072 from Immigration Woodlands Checkpoint to the carpark at Woodlands Cinema without any authorization under the said Act or the regulations made thereunder and you have thereby committed an offence under s 5 (a) and punishable under s 33 of the Misuse of Drugs Act.

Case for Prosecution

2 The evidence adduced by the Prosecution proves beyond any doubt that the accused did traffic in a quantity of diamorphine on the day and time in question. The accused was arrested near his car and a plastic packet was found in the glove compartment thereof as a result of a trap laid for him by the officers of the Central Narcotics Bureau (“CNB”). The entrapment was made possible when the accused tried to reach one Lim Lye Huat through Lim's pager when Lim was in the custody of the CNB officers after his arrest for trafficking, possession and consumption of a similar drug. Lim was instructed by a CNB officer to arrange for the officer to buy about a lb of heroin from the accused. The arrangement was successfully made and it led to the arrest of the accused with a plastic bag containing a pinkish granular substance.

3 The evidence adduced by the Prosecution to prove that the weight of the diamorphine in the plastic packet was not less than 18.77g is as follows. After the accused was arrested, he and his wife (who was with him in the car at the time of the arrest) were taken to CNB headquarters. The plastic packet and all the other things that were seized from the accused and his wife were also brought to CNB headquarters. The packet was weighed on 30 September 1986 and found to weigh 111.4g.

4 According to NO Lee Kiong Lock, he sent the plastic packet to the Department of Scientific Services (“DSS”) on 30 September 1986 at about 11.40am for analysis and report. DSS received the packet and an analysis was done. For convenience, we shall...

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