A long list of blood-stained exhibits found in the Bain family home were never sent for forensic testing, a jury at the High Court in Christchurch has been told.
David Bain, 37, accused of shooting his father Robin, mother Margaret, brother Stephen and sisters Arawa and Laniet in their Dunedin home on 20 June 1994.
The defence says Robin Bain killed the family members present in the house before using the accused's rifle to shoot himself.
Forensic evidence is a crucial part of the Crown's case against David Bain, which continued on Wednesday.
The jury was told that numerous items from rooms in the house that were found to have blood on them were not sent to Environmental Science and Research (ESR) for testing.
They included a sheet from Stephen Bain's bedroom, clothing Laniet Bain was wearing and various parts of the house on which blood was identified.
The defence says the case was never investigated properly and that David Bain was wrongly arrested, as it was Robin Bain who committed the murders.
The court was told that no particles of gunshot powder were found on Robin Bain's hands when samples were tested in the laboratory.
Peter Hentschel, a former ESR scientist involved in testing the exhibits, was asked by Crown prosecutor Keiran Raftery to explain the testing process.
Mr Hentschel told the court a body could still be tested with accuracy up to three hours after death.
On Tuesday, Mr Hentschel, told the court a living person's hands must be tested for firearms discharge residue within three hours. Any movement, or handwashing, would cause the residue to disappear.
Police have come under scrutiny from Mr Bain's defence lawyers for not running the tests soon enough.
Mr Hentschel told jury on Wednesday that forensic tests found blood on the soles of David Bain's socks. He told the Crown prosecutor that the socks were treated with luminol and both gave a positive reaction for blood.
Judge acknowledged in Bain book
The judge hearing the David Bain retrial says he has no idea why he is acknowledged in a 1997 book about the case.
The Mask of Sanity, written by James McNeish, looks at David Bain's first trial on murder charges.
In it, Mr McNeish acknowledges Justice Panckhurst, who is hearing Mr Bain's retrial, although the judge says he would not have had any information about the Bain case at the time the book was written.
A Justice Ministry official contacted the author and their interaction was discussed in court on Wednesday morning.
Mr McNeish said he has no recollection of the judge's involvement but that his lawyer advised him not to speak about the matter.
Defence layer Michael Reed, QC, told Justice Panckhurst the author's refusal to clarify made it seem there might be something not being said, but the judge said there was little more he could do.