The wounds Henri van Breda sustained the morning his parents and brother were murdered were superficial and typical of self-inflicted injuries, the Western Cape High Court heard on Thursday.
The only injuries he was unlikely to have caused were those on his head, back, and leg, clinical forensic specialist Dr Marianne Tiemensma testified.
She examined photos and records of Van Breda's injuries. According to her findings, he had "regular and superficial" incisions on his chest, which were not life threatening. The cuts had equal depth, origin and termination, were parallel and avoided sensitive areas such as the nipples.
"It is unlikely for a victim who is being attacked to stand still and not take defensive or evasive action to allow such multiple and uniform injuries to be executed," she found.
Tiemensma believed the cuts were in a "reachable" area for being self-inflicted. She came to the same conclusion regarding the wounds on his right forearm. Van Breda is right-handed.
"This is not a typical area where one would expect 'defence wounds' with sharp instrument attacks. Defence wounds are more likely to be found on the ventral/palmar aspect of the forearm or wrist, elbows, palmar surface of the hand in an attempt to grab the weapon, or on the backs of the hands or fingers from non-grasping movements in attempt to ward off a weapon."
The sharp-force injuries to his thorax and abdomen had a slightly different appearance and appeared to have been inflicted with a stabbing, and not a slicing, action, Tiemensma found. These too were superficial.
She said Van Breda's claims that the knife became stuck in one of the stab wounds was virtually impossible, as the wound was only 10mm deep, in comparison with the size and shape of the knife.
To get though skin and tissue would have taken 40mm or more for someone of Van Breda's size, Tiemensma testified.
Typical defensive injury
The swelling above his left eye and a bruise under the eye - indicated blunt force injuries, likely the result of trauma to the face and forehead, such as a blow or a fall.
The scratches and abrasions to his back were typically from blunt force trauma, and also unlikely to have been self-inflicted. The same could be said of the injuries to his right leg.
His injuries could be consistent with falling on the stairs, she said.
The 22-year-old is on trial on charges of murdering his parents Martin, 54, and Teresa, 55, and brother Rudi, 22, with an axe, attempting to murder his younger sister Marli, and defeating the ends of justice.
He has pleaded not guilty and alleges a balaclava-clad intruder attacked the family in their home in the De Zalze estate, Stellenbosch, in the early hours of January 27, 2015.
Tiemensma testified that Marli had what looked like sharp-force injury to the wrist. It was a typical defensive injury, possibly from using her hands to ward off an attack. The bruising to the back of her hands and on a knuckle, and a small abrasion, were injuries which could be seen in someone fighting back.
Earlier on Thursday, Sergeant Jonathan Oliphant of the police's criminal records centre, told the court he found 53 prints at 12 Goske Street. They included those of the family, two domestic workers, a gardener, and Marli's ex-boyfriend James Reade-Jahn. The others were unidentifiable.
Van Breda's right thumb print was found on the blade of the knife. No prints were found on the axe.
Oliphant said he checked the boundary wall for prints with his naked eye, with a special light and by spraying a chemical. He found no prints or sings of activity.
The trial resumes on Monday.