The prosecution failed to prove its case beyond a reasonable doubt that Henri van Breda axed his family to death in their De Zalze home three years ago, defence advocate Pieter Botha argued in the Western Cape High Court on Tuesday.
The onus was on the State to prove that his client had been the one who committed the triple murders and attempted to kill his sister, Botha said.
"But the evidence points the other way and at the very least creates reasonable doubt."The prosecution had no eyewitness accounts or direct evidence, Botha pointed out, and its case was circumstantial.
"The State's case is that no one else could have committed the crimes, and the accused's version of other assailants is not reasonably true."
But Van Breda's version can only be rejected if it can be said "it is so improbable it can't be seen as possibly true".
Botha argued that the State had given the impression that the De Zalze Golf Estate was impenetrable, but Judge Siraj Desai countered that the argument was that it was so secure that it was unlikely that a third party could have gained access without the expertise "that Ocean's Eleven displays".
Botha said the onus was not on his client to prove that someone had not entered that night.
He insisted that the DNA results could not be relied on, as defence witness Dr Antonel Olckers had found that standard operating procedures were only followed in the testing of 23 of the 151 samples.
When asked by Desai if he should reject the DNA evidence, Botha said it couldn't be relied on as it was not scientifically reliable.
He pointed out that the SAPS forensic science laboratory was not accredited, and that analyst Lieutenant Colonel Sharlene Otto had not passed a proficiency test.
Desai asked why the defence had not retested the samples, and Botha said he had made this call because retesting would have been too expensive and his client would have "been out of funds a long time ago".
Botha also said there was no evidence of an argument on the night of the murders, despite the testimony of neighbour Stephanie Op't Hof who said she heard raised voices coming from 12 Goske Street.
He maintained that she could only have been hearing Star Trek 2, which the Van Breda men had ostensibly been watching.
He said video footage of the crime scene indicated that people had been sitting on the couch and a DVD was recorded as being next to the TV.
De Zalze security officer Edgar Wyngaard had also not heard any disturbance emanating from the Van Breda home and had been within 40m of the house during his patrols.
Botha said neither Henri nor Marli had told their respective girlfriend or boyfriend of any argument that night. Op't Hof had also been unable to determine the language, how many people were involved, or what was being said, Botha said. He believed she had been biased.
This, he said, was displayed when she said she hadn't known at the time that Van Breda "was busy attacking his family" that night.
Botha also argued that the blood stains on Van Breda did not mean he was the attacker, as it only placed him in the immediate vicinity, corroborating his testimony.
The fact that no blood belonging to Teresa or Marli was found on his shorts also supported his version that he had not been close by when his mother and sister were attacked, Botha said.
Botha said the absence of Marli's blood on the axe, despite being hit with it eight times, showed there was a possibility that another weapon was used on her by a second attacker.
Judge Desai questioned why someone would carry an axe to a home invasion, and Botha responded that gratuitous violence was rife in SA.
Allegations that Van Breda had tampered with the scene by moving the duvet, as well as Rudi's body, could be explained by pathologist Dr Daphne Anthony's testimony, when she conceded that Rudi was probably still able to move after the assault, even if not purposefully.
He may have pulled the duvet, Botha said.
Van Breda, 23, 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 clothing, was behind the attack, and that he had heard other voices, of people speaking Afrikaans, in the family's Stellenbosch home 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.
Botha also argued that his client made a very good witness and his version had remained consistent from the start.
He will continue with his closing arguments on Wednesday.