Cape Town - Although it seemed as though all standard operating procedures were not adhered to, the samples collected from the Van Breda triple murder scene were not contaminated, chief forensic analyst Lieutenant Colonel Sharlene Otto told the Western Cape High Court on Friday.
Murder accused Henri van Breda’s defence attorney Advocate Matthys Combrink produced photos of the laboratory at the time samples were tested which showed staff not wearing shoe covers, as required in its standard operating procedures.
Otto conceded that processes appeared to not have been followed, but insisted that if contamination had taken place, the person’s DNA would have been found in the sample results.
She also said the person not wearing the full protective gear would not necessarily have been working with the samples, and would therefore not be required to be completely covered.
The court heard on Monday that DNA belonging to Rudi and Teresa van Breda was found under Henri’s fingernails.
It also heard that DNA belonging to Henri, Rudi and Teresa was found in a corner of the shower, but on Friday Otto said it was possible that it was that of only two of them as it was a mixture sample.
No unknown DNA was found in the family’s luxury De Zalze Estate home.
Van Breda, 22, pleaded not guilty to axing his parents and brother to death, seriously injuring his sister Marli and defeating the ends of justice.
He alleged that an intruder wearing a balaclava, gloves and dark clothes was behind the attack, and that he had heard other voices of people speaking Afrikaans in their home in the De Zalze Estate in Stellenbosch in January 2015.
Van Breda claimed that, after a fight with the axe-wielding intruder who was also armed with a knife, the man had escaped.
No reason to doubt results
Otto told the court that a person wearing a balaclava and gloves involved in a struggle would not leave a lot of DNA as the face and head area are “huge shedders”.
She also referred to the Locard principle, explaining that if an attacker is covered and involved in a struggle, the attacker wouldn’t transfer DNA onto the other person, but that person’s DNA will be on the attacker.
She in her evidence in chief testified that Martin's right-hand nail scrapings showed Rudi’s DNA, while a swab taken from the handle of the knife used in the attack – which comes from the family’s kitchen – only matched Rudi.
She confirmed that a total of 216 samples were submitted from the scene and tested.
After a full week on the stand, Otto appeared exasperated as the defence questioned the DNA results.
She said nothing had gone wrong with the submitted samples as they were done in isolation and there was no reason to doubt the outcome of the results.
Otto, who described herself as an objective witness who relied solely on the DNA for her reports, told Combrink to take the samples and have it tested if he questioned the results.
Her job, she said, was to “compare and relay".
Earlier this week, she said while the police’s forensic science laboratory was not accredited, this did not make its results less reliable. She testified that the only difference between an unaccredited and accredited laboratory was an audit by the South African National Accreditation System, which was not a legal requirement in South Africa.
The police’s forensic laboratory followed strict and stringent quality control systems and complied with international standards and guidelines, Otto maintained.
The trial continues on Monday.