Rudi van Breda had been dragged or moved after being axed, a blood stain pattern analyst testified in the Western Cape High Court on Monday.
Captain Marius Joubert of the SAPS Forensic Science Laboratory in Plattekloof testified that Rudi's blood had already started to clot when he was taken from the bed to the floor where his body was found, resulting in swipe and wipe patterns in the blood.
Joubert had also noticed a void on Henri's bed. According to him, there was an absence of spatter in an "otherwise continuous blood-stained area".
"The void was most probably created by the presence of an intervening object, which was removed ..."
Joubert testified on the various blood spatters he analysed following the bloody murders at 12 Goske Street, De Zalze, in January 2015.
A chemical sprayed in the shower of the Van Breda brothers' en suite bathroom found microscopic evidence of blood on the shower handle, the wall above the tap, beneath the shower head and on the floor.
The blood belonged to Henri, Teresa and Rudi, according to DNA results.
Blood stain pattern
He painstakingly went through each stain, its possible cause and exact location, stretching from the entry of the family's Stellenbosch home to the drops that had fallen from the first floor where the bodies were found.
Joubert, a policeman with 27 years' experience who started investigating crime scenes in 1993, explained to the court that blood stain pattern analysis could provide information on how a crime was committed.
Earlier in the trial, chief forensic analyst Lieutenant-Colonel Sharlene Otto confirmed DNA was collected from the shower and was found to belong to Henri, his brother and mother.
During cross examination, she confirmed there was not a distinction between the three people, as the three reference samples are "read into" the examined sample.
Henri and Rudi would have 50% DNA from Teresa and it was possible that it only contained two of the three's DNA, she conceded, but insisted all she was required to do was compare the mixture to the references.
No unknown DNA was found on the crime scene.
In addition to the numerous spatters photographed and sketched inside the family's luxury home, blood spatter belonging to Rudi was also found on an external wall, possibly indicating with how much force he had been axed.
More than 50 blood stains were found on Henri's shorts: 35 stains belonged to Rudi, 9 to Henri, 5 to Martin and 3 were mixed samples. None belonged to Marli.
Multiple spatter stains were examined on Henri's white socks, and Joubert said this was caused by being in close proximity to the source.
Joubert testified that force was applied to the source and that the blood had landed on the socks.
Blood samples - 9 from Rudi, 1 from Martin, 1 from Teresa and 2 from Henri - were found on the top and sides of Henri's socks.
Van Breda's murder trial resumed after it was postponed last month when Joubert took ill.
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 multi-million rand home on the highly-secured estate.
Van Breda claimed that, after a fight with the axe-wielding intruder who was also armed with a knife, the man had escaped.
But the investigating officer, Sergeant Marlon Appollis, had told the court that no one matching the accused's description of the axe man had ever been found, despite police informants and newspaper appeals being used to locate him.
The trial resumes on Tuesday.