Dean Cottle and his relationship to Bain's sister L' />

A warrant has been issued for the arrest of a man David Bain's lawyers want to give evidence.

Dean Cottle and his relationship to Bain's sister Laniet, 18, has been referred to in evidence in the Bain murder retrial in the High Court at Christchurch.

A friend of Laniet's has given evidence that Mr Cottle was blackmailing Laniet over her work as a prostitute and requiring her to have sex with him at least once a week and do "horrible and graphic things".

The court heard today that Mr Cottle was being sought by police so he could be brought to court to give evidence.

However, Bain's lawyer Michael Reed QC said he understood police had been unable to find Mr Cottle at either his home or work, which was not surprising. Mr Reed said that if Mr Cottle could not be found, he wanted excerpts of a formal statement previously given by him to be read to the court.

Aside from Mr Cottle, Mr Reed said all of the defence's witnesses had been heard. The prosecution are still to cross-examine another witness via video link from the United Kingdom.

David Bain, 37, is on trial for the murder of his parents and three siblings in their Dunedin home on June 20, 1994. His defence team say his father, Robin, 58, shot dead the family before committing suicide with the rifle.

Earlier, the court was told an object such as a cushion was placed between Laniet Bain and the rifle used to kill her.

Victorian forensic scientist Peter Ross, whose past work has included looking into the disappearance of Azaria Chamberlain in the famous Australian "Dingo" case, analysed various bullet fragments found in Laniet's bedroom after she was shot dead. He found traces of raw white cotton and yarn on the fragments.

Mr Ross said that fragments were found on the body and at least a metre away from Laniet, who was shot in the cheek, above the left ear and on top of the head while in her bed. The wound to the top of her head was unusually large for the .22 rifle ammunition involved, he said.

Laniet's brother, David Bain, is on trial for murdering her and four other members of the family.

Mr Ross said his findings indicated that something was placed between the muzzle of the rifle and the top of Laniet's head. He could not say where this object was placed.

Asked if anything was found in Bain's house that could have been used in this way, Mr Ross said there was not. Mr Ross said it was possible this object was overlooked, or taken away.

Prosecutor Cameron Mander put to Mr Ross it would be incredible for this object to be overlooked, because it would be covered in blood. Mr Ross said there would be blood on it but it would not be covered

Mr Ross said the evidence was compelling that the bullet that struck Laniet had passed through a fabric object.

The order of the shots Laniet suffered is considered important as to whether Bain heard his sister gurgling if he shot her.

Bain told police he heard Laniet gurgle when he returned to his home after the shootings, but the prosecution say he must have heard this noise after inflicting the first shot to Laniet's cheek, which she would have survived.

Mr Ross said it was virtually impossible for Laniet to have suffered the shot to the top of her head in the position she was found, lying on her back in her bed.

She must have been upright in her bed with her head facing towards the killer and muzzle of the gun because "bullets don't travel around corners, unless they ricochet".

Therefore Mr Ross believed the shot to the top of the head was the first Laniet suffered, and she then slumped back onto her bed.

The second shot was above her ear, Mr Ross said. The third shot, to Laniet's cheek, left an undisturbed flow of blood.

Experts in Bain's defence have stated that gurgling noises could have come from Laniet even after her death.

Mr Ross said that early in his career he was called to a case of a woman whose body produced a groaning noise about an hour after she was declared dead.