The fatal gunshot wound suffered by David Bain's father Robin was likely from a rifle fired a short distance away rather than virtually against his head, a court has heard.

In the High Court in Christchurch today, pathologist Kenneth Thomson disagreed with the evidence of a previous pathologist, Alexander Dempster, who described the wound to Robin Bain's left temple as an angled near-contact wound, where the silencer of the . 22 rifle would have been virtually pressed against the head.

Dr Thomson said his view was that the gunshot wound suffered by Robin was an "intermediate range" wound. Testing indicated this bullet could have been fired from 16 to 20cm away.

The range is considered important as to whether Robin shot himself.

David Bain, 37, is on trial for shooting dead his parents and three siblings, but his defence team are arguing that his father Robin shot the rest of the family before turning the .22 rifle on himself.

Dr Thomson also told the court David's sister Laniet, 18, likely survived being shot in the cheek and was sitting up in her bed when she was shot again with the rifle hard against the top of her head.

Dr Thomson said he believed that Laniet may have initially lost consciousness but regained it and sat up after what he believes was the first shot through her cheekbone.

Evidence has previously been given about whether Laniet could have survived long enough after to be heard gurgling by David Bain when he says he returned home from his morning paper round on June 20, 1994.

In order for her to gurgle, Laniet would have had to been still alive, Dr Thomson said.

"She must have been making some sort of respiratory effort. If she had ceased to be breathing then there would be no noise unless someone perhaps attempted to move her."

Laniet suffered three gunshot wounds, and either of the last two, to the top of the head or left side of the head above her ear, would have been fatal because the bullets passed through major brain structures. The final shot may have been unnecessary because she was already dead.

Dr Thomson said he believed the first wound she suffered was through her cheek, and she could have lost consciousness but survived and sat up in her bed.

She had inhaled blood, indicating she had continued breathing for some period after being injured.

He believed the second and third shots would have been fired as she half-sitting in a semi-upright position, and either would have been fatal.

The wound she suffered to the top of her head would have been with the rifle and attached silencer pressed hard against her head, Dr Thomson said.

Yesterday, defence lawyer Michael Reed QC described the shooting of Laniet as an execution by a deranged person.

Robin Bain, 58, was lying in the lounge of the Bain home, with the rifle beside him and blood splattered on curtains leading to an adjoining alcove.

Another pathologist, Alexander Dempster has previously given evidence that it was unlikely that Robin shot himself.

Dr Thomson said today it would have been only milliseconds between Robin sustaining the gunshot wound and the blood spray hitting the curtains. Robin would likely become immediately unconscious and have collapsed in a second or two.

David's mother, Margaret, 50, suffered a gunshot wound in her left eye as she lay in her bed, and would have suffered unconsciousness, but could have survived for a period after being shot.

Dr Thomson said the rifle was either held above her head, or her head was slightly forward when she was shot. Or she my have had her head turned.

He believed the rifle would have been very close to her when the shot was fired. He said there was no possibility of deliberate movement after Margaret was shot.

David's sister, Arawa, 19, had a gunshot wound to the right side of her forehead, and the wound indicated the shot was likely "distant" - fired from at least 18 inches away.