The first shot came from defence advocate Matthys Combrink who accused chief forensic analyst Sharlene Otto of talking “nonsense” in reference to her claim she had passed a recent proficiency test.
Combrink had the case study in court and said Otto's lab was one of three to only report that semen was found in a sample containing blood and semen.
There were 129 other forensic labs that had reported both blood and semen, Combrink said. “If I had come to you, you wouldn't have told me there was a woman involved.”
Otto said considering the case study probably involved a victim of sexual assault, the semen was what was needed to be collected.
Combrink later made reference to a DNA exhibit and put the marking to Otto, which read: “1 KS”. Combrink asked Otto what that meant and Otto explained it was the first sample an expert initialled “KS” took.
“The second sample would be ‘2 KS’ and so on,” Otto said.
Combrink then asked Otto if she meant the marking was alphanumeric, to which Otto responded “yes”. When Combrink again referenced a sample and asked Otto where the signature of the expert was, Otto said “KS” was the signature.
Combrink said to Otto that what she had claimed to be the signature was in fact the alphanumeric, as he previously put to her.
Otto replied: “You don't know much about maths.”
Van Breda is on trial for the murder of three family members in Stellenbosch in January 2015.
The trial continues.