An arrest warrant has been issued for a defence witness due to give evidence in the retrial of David Bain.
The Crown says David Bain, 37, killed his parents Robin and Margaret and siblings Arawa, Laniet and Stephen at the family's house in Dunedin on 20 June 1994.
The defence says Robin Bain killed the family present in the house before shooting himself because Laniet Bain was about to reveal an incestuous affair.
Police have been trying to find Dean Cottle so he can be brought to give evidence in the High Court in Christchurch.
Earlier in the trial, the jury was told about Laniet Bain's relationship with Mr Cottle, who it is alleged was threatening to reveal to her parents that she was working as a prostitute.
Defence lawyer Michael Reed, QC, told the court on Tuesday that police have been unable to find Mr Cottle at his home or business.
Mr Cottle would be the last witness called by the defence, but if he cannot be found it wants some of his evidence read to the court.
Evidence on bullet fired at Laniet Bain
Australian forensics expert Peter Ross gave evidence for the defence on Tuesday and told the court the position of the shot through the top of Laniet Bain's head indicated that she was shot while sitting up.
The Crown evidence is that Laniet Bain was shot first through the cheek, a survivable wound which meant David Bain heard her gurgling and subsequently shot her twice more.
However, Mr Ross said that Laniet Bain was first shot from a distance as she was sitting up, the bullet passing through something like a cushion before hitting the top of her head.
The second shot was above her ear, the third was to her cheek.
While the Crown says David Bain's admission of hearing Laniet Bain gurgling indicates he was the killer, Mr Ross gave evidence that it is possible for noises to come from dead bodies.
The defence argues that Laniet Bain was not alive when David Bain saw her.
The Crown has still to complete its cross-examination of a defence fingerprint expert who gave evidence last week but has since returned to Britain.