Bloodstained curtains and the position Robin Bain's body was found in indicated it could have been moved, the High Court heard today.
Forensic pathology professor James Ferris told David Bain's murder trial that there were some issues with regard to the position of Robin's body that concerned him.
Robin Bain, 58, suffered a fatal gunshot wound to his left temple on the morning of June 20, 1994. The prosecution say the shot was fired by his son David Bain, but the defence say it was a self-inflicted wound.
David Bain, 37, is on trial in the High Court in Christchurch for the murders of his parents and three siblings. His defence team say Robin shot dead the family before turning the .22 rifle on himself.
Professor Ferris raised the possibility that Robin's body was moved after he died of the gunshot.
Large blood "splashes" on a curtain some distance from his body were not a result of the firing of the gun into Robin's skull.
In order to produce these stains, the already sustained wound must have been dripping blood down the curtain, Professor Ferris said.
"The only way these could occur would be if his body had been moved and blood had effectively shaken out of the holes."
Professor Ferris earlier said it would have been impossible for Robin Bain to have committed suicide because of the range at which he suffered a fatal gunshot wound, the High Court has been told.
He said he compared the features of the wound Robin suffered, in particular the presence of powder marks, to test firing from various distances on card and pig skin.
From this he calculated that the shot that killed Robin would have been fired from 30 to 42cm away.
Asked about the possibility of suicide at this range, Professor Ferris said: "In my view it would be simply impossible to self-inflict the injury we see".
"I think range is probably the most important factor."
Professor Ferris yesterday pointed a number of tiny abrasions around Robin's gunshot wound, which he said were characteristic of the impact of unburnt powder against the skin. This indicated an "intermediate range wound".
Two other pathologists have given separate views on the range of the rifle from Robin's head when fired - one that it was virtually against the head, and another that it could be 16 to 20cm away from the head.
David Bain's defence team have put forward a range of scenarios in which Robin could have shot himself with the rifle silencer against his temple.
Test firing on card and pigskin were carried out to assist with ascertaining the range of a bullet fired. The scatter of power marks around the bullet hole was the most important feature for showing how far the rifle was from the target, Professor Ferris said.
He said the nature of the wound Robin suffered meant that he would have collapsed immobile and dead or dying instantly. This would likely mean he dropped straight to the floor.
Professor Ferris said suicides with rifles were rare in his experience.