PROOF OF CORRECTNESS OF MEASURING INSTRUMENT

S v EKE 2016 (1) SACR 135 (ECG)

Evidence — Certificate in terms of s 212(4)(a) of Criminal Procedure Act 51 of 1977— Traffic offences — Effect of certificate — Proof of correctness of measuring instrument — Sufficient if certificate set out qualifications of person who made it, described process involved and explained why was reliable — Constituting prima facie proof if accused does not rebut it.
At the accused’s trial in a magistrates’ court on a charge of having contravened s 65(2)(a) of the National Road Traffic Act 93 of 1996, in that she had driven a motor vehicle whilst the concentration of alcohol in her blood exceeded the permissible limit of 0,05 grammes per 100 millilitres, the appellant pleaded not guilty but made a number of admissions in terms of s 220 of the Criminal Procedure Act 51 of 1977. She admitted that: (1) she had driven the motor vehicle on a public road; (2) that a sample of her blood was drawn within the prescribed period and that the result of the analysis of the blood sample was 0,15 grammes per 100 millilitres. In her plea explanation her attorney expressly placed in issue the accuracy and reliability of the blood specimen measurement process, namely whether the instruments used to analyse the blood sample — gas chromatographs — had been properly calibrated before the sample was analysed. The prosecutor handed in a certificate in terms of s 212(4) and (8) of the CPA in which the deponent stated that she had a diploma in analytical chemistry, and described herself as an assistant forensic analyst employed by the state at the Forensic Chemistry Laboratory of the Department of Health in Cape Town. She stated that she had analysed the blood sample by means of a method described in paras 5 – 6 of the certificate and that she had obtained the result of the concentration of alcohol in the blood sample. She stated that the result was established by gas chromatography and the blood specimen was analysed in duplicate. The two gas chromatographs used were calibrated before the specimens were analysed and the calibration was done by using certified alcohol standards of different concentrations to obtain a calibration curve. The certified standards were supplied by the National Metrology Institute of South Africa which was the custodian of the national measuring standards in the country. She explained in detail the process and that the reliability of the gas chromatographs was constantly checked by having recourse to the reproducibility of the retention times of the compounds on the column, baseline appearance and resolution between alcohol and internal standard peaks. In addition, a quality-control specimen was chromatographed regularly to verify instrument performance. This proved that the gas chromatograph was set up and operating properly. After the certificate was handed in the prosecutor closed the state’s case and the appellant also closed her case without tendering any evidence. She was convicted of the offence and sentenced to a fine of R4000 or eight months’ imprisonment, part of which was suspended. In an appeal against the conviction the appellant contended that the proper calibration of the gas chromatograph could not be proved by way of a certificate in terms of s 212(4) but only by way of an affidavit in terms of s 212(10). The court noted that two issues arose on appeal: (a) whether the s 212(4) certificate could be used to prove the proper calibration of the gas chromatographs; and (b) if so, whether the mere placing in issue of the accuracy of the result obtained from the gas chromatographs was sufficient to disturb the state’s prima facie case.

Held, that a certificate, in the circumstances permitted by s 212(4), took the place of oral evidence, and a mere recording of a result would not suffice if an expert witness gave oral evidence, and it did not suffice for purposes of a certificate, and, that being so, the certificate of necessity had to contain more than merely the result. In order to be of any use as evidence it also had to set out the qualifications of the person who made it, describe the process involved and explain why it was reliable. The certificate procedure, while not intended to reduce the burden of proof that rested on the state, was intended to facilitate the procurement of certain evidence of an expert nature, and the purpose of s 212 was simply to avoid undue wastage of official manpower in court attendances for the purpose of frequently undisputed evidence on matters nearly always incontrovertible.
Held, further, that the first leg of the appeal, namely that the accuracy of the results produced by gas chromatographs could only be proved by an affidavit in terms of s 212(10) and not by a certificate in terms of s 212(4), had to fail.
Held, further, that a plea explanation was evidentiary material because it was the unsworn statement made by an accused in which he or she disclosed what was in issue between him/her and the state. In cases in which an accused did not testify, while a plea explanation was not on the same footing as evidence having been given under oath, nevertheless it had to be considered in finally deciding whether the state had proved its case beyond a reasonable doubt. This did not mean that the plea explanation on its own could displace the state’s prima facie evidence. Instead, by identifying the issues in dispute between the parties, it identified what the state was required to prove in order to secure a conviction.
Held, further, that there were three possible courses open to the appellant to rebut the correctness of the result recorded in the certificate. She could have applied to the court below to exercise its discretion in terms of s 212(12) to have the analyst subpoenaed to give oral evidence or she herself could have subpoenaed the analyst to testify. If she had a factual basis to cast doubt on the accuracy of the result (such as that it could not be accurate as she consumed no alcohol at the time concerned), she herself could have testified or called witnesses. In the circumstances, there being no evidence to rebut or challenge the certificate, its contents, having been prima facie proof, became conclusive proof. The appeal was accordingly dismissed.

Advertisements