A weapons specialist who testified in defence of murder-accused David Bain has been recalled to the stand after a new test proved his evidence was wrong.
Philip Boyce, a weapons expert from Britain, has given evidence at the High Court in Christchurch where Mr Bain is being retried for murder.
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.
On Monday, Mr Boyce told the court that Robin Bain shot himself and could have held the rifle up to 22 centimetres away from his head to do so.
However, Mr Boyce admitted that he had not physically tested the possibility of that distance being correct and was recalled to court to do so on Tuesday.
Mr Boyce told the jury he was wrong by 10cm and that, given Robin Bain's armspan, the 58-year-old could have only held the rifle up to 12cm from his head.
Lens planted, says defence
More conflicting evidence about the area where key evidence was found was presented in court on Tuesday.
The defence says a lens from spectacles linked to David Bain was planted by an officer on the original case to strengthen the police case against the accused.
Two weeks ago a Crown witness attempted to disprove that theory, saying the lens had been visible in Stephen Bain's bedroom from the first day and would, therefore, simply have been moved to where it was eventually found when the body of Stephen Bain was removed.
But that debate resurfaced on Tuesday, with new photography expert Peter Durrant giving evidence for the defence.
Mr Durrant said scene photos show that a jacket in Stephen Bain's room was disturbed, which supports the defence's theory that the lens was planted.
The Crown says the lens links David Bain to the murder of Stephen Bain because the matching frames and other lens were found in the accused's bedroom.
Bloody footprints not David Bain's - witness
Defence witness forensic scientist Anna Sandiford told the court on Tuesday her tests showed David Bain could not have left the bloodied sockprints recorded at the family home.
Anna Sandiford told the court that the tests she carried out involved having David Bain dip a sock-encased foot in pig blood, then walk on carpet. She measured the prints, before and after coating them with luminol.
Bloodied footprints were found in the Every St house after luminol tests were carried out and police say they were made by the killer who went room to room, shooting the family members.
The prints were not visible to the naked eye, but were found to measure 280mm.
Dr Sandiford said her tests showed that David Bain's footprints, when measured, were never less than 300mm.
"Based on the results of the tests I conducted, David Bain's right foot could not have made the complete bloodied sockprints recorded at Every St," she told the jury.
Robin Bain asked for relief teacher
The court heard evidence that Robin Bain tried to find a relief teacher just days before he and four others in his family were killed.
Relief teacher Christine Rout told the court that in the week before the deaths, Robin Bain phoned her at home in the evening to ask whether she could relieve for the following weeks.
The assignment would have begun on Monday 20 June, the day the five Bain family members died.