S v MATSHABA 2016 (2) SACR 651 (NWM)
Evidence — Expert evidence — DNA analysis — Presentation of such evidence — Chain of handling of samples from collection to analysis to be properly presented.
The appellant was convicted in a regional magistrates’ court on a charge of housebreaking with intent to rape and rape and was sentenced to life imprisonment. His conviction was based on DNA evidence which linked his blood type with that found on the complainant’s nightdress. There was, however, no evidence that the appellant’s blood sample was sealed or what number was allocated to it. The forensic expert’s evidence lacked reference from whom the samples of blood were received, contrary to what was provided for in s 212(8)(a)(ii)(aa) of the Criminal Procedure Act 51 of 1977. The investigating officer also testified that he was not the one who delivered the samples to the laboratory for testing, but that it was another police official whom the state failed to call. There was also no evidence in relation to the gathering, marking and storage of the samples. On appeal against the conviction,
Held, that the importance of proving the chain of evidence was to indicate the absence of alteration or substitution of the exhibits. If no admissions were made by the defence, the state bore the onus to prove the chain of evidence and it had to establish the name of each person who handled the evidence, the date on which it was handled and the duration. Failure by the state to establish this chain of evidence affected the integrity of the evidence and rendered it inadmissible. The sequence from collecting of the samples to the DNA-testing was accordingly flawed and the conviction and sentence had to be set aside.