The retrial of David Bain has seen three months of evidence and over 180 witnesses take the stand for the defence and the prosecution. nzherald.co.nz looks at some of the key points on which the case turned.
WHO TURNED ON THE FAMILY COMPUTER?
A message found on the Bain family computer, on the same morning that five Bain family members were found dead in their home, read: "Sorry you are the only one who deserved to stay".
Exactly when the message was written on the computer cannot be established, but complex evidence has been debated in court on when the computer was started. This timing is important in relation to sightings of Bain on his paper run that morning.
Computer expert Martin Cox ran a test on the Bain family computer on the day after the killings. He said the computer clock was not set, so Mr Cox recorded the time he saved the message.
He used the time difference to establish what time the computer would have been turned on the day before. The result he produced was 6.44am. But after agreeing that the detective's watch had been estimated to be two minutes fast, he agreed it would be about 6.42am.
Maarten Kleintjes prepared a series of theoretical calculations based on data from a cloned version of the Bain computer and timings from a police detective's watch. Part of his calculations was guessing and assumption, he told the court.
Computer scientist Dr Bryan Thomas said there was no way it could have taken Mr Cox six minutes to save a message found on the Bain family computer.
He said it would have taken him between one and two minutes but confirmed that the police and Mr Cox were the best people to estimate what time the message was saved, given they were there on the morning after the killings.
WHEN DID BAIN COMPLETE HIS PAPER ROUND?
The prosecution say Bain used the paper round to try to create an alibi for the murders he committed.
Witnesses have given varying accounts of seeing Bain delivering papers, including some who say he acted differently on June 20, or was earlier than normal.
Senior constable Malcolm Parker told the court that he noticed his paper in the driveway just after 6.35am and sat down to have coffee and read the paper at 6.38am.
"It was unusual because I had never got the paper that early," he told the court.
The defence says the murders were committed between about 5.45am and 6.45am when Bain was out on his paper round.
They say Bain arrived home after the paper round to find his family dead. The defence team say the timings mean he could not have turned on the computer in the house and written the message found on the computer.
DID ROBIN BAIN COMMIT SUICIDE?
ESR forensic scientist Kevan Walsh said the rifle was a distance away from Robin Bain's head. Mr Walsh calculated the rifle was most likely more than 20cm from Robin's head when fired.
Forensic pathology professor James Ferris ruled out suicide based on his view that the rifle was fired between 30 and 42cm from Robin's head.
Pathologist Alexander Dempster said the rifle was virtually up against Robin's head when fired, which the defence says is about the position the rifle was in when Robin committed suicide.
Forensic pathologist Dr Robert Chapman said Robin's wound was consistent with suicide.
But under cross examination he agreed that he could not say if Robin had committed suicide or not, having not heard all the evidence at the trial. 28
WHAT DID BAIN SEE AND HEAR?
The prosecution say Bain told an emergency call receiver that "They are all dead" but later told police that he had only seen the bodies of his mother and father.
Detective Gregory Dunne said when he asked Bain how he knew his whole family were dead when he had seen only his parents, he replied: "I don't know."
Bain also told police he could not explain a period of 25 minutes between finding his parents dead and calling 111, but said he had been "spacing out" over the past couple of months.
Bain changed his version of events to say that he had discovered the bodies of his siblings, after initially telling police he found only his mother and father lying dead.
"When I was interviewed by the detectives, I made it clear that I did not go into any of the other rooms, other than my mother's and my father's room," Bain said in his evidence to his first murder trial in 1995. "I said that to the detectives because I didn't remember."
Bain told the 1995 trial it was only after sessions with a clinician months later that he remembered going into the bedrooms where his brother and sisters lay dead. Bain's evidence from his first trial was read to the jury by Judge Graham Panckhurst.
Dr Philip Brinded, a forensic psychiatrist who visited Bain in prison, said that experiencing post trauma amnesia was not an indicator of guilt or innocence.
DID DAVID BAIN HEAR LANIET GURGLE AND DOES THAT MAKE HIM THE KILLER?
David Bain told police that he heard his sister gurgling when he arrived home on the morning of the shootings.
The prosecution say Bain must have shot Laniet to hear her gurgle, because this noise could only have occurred following the first shot Laniet suffered to her cheek. The next two shots were fatal, the prosecution say.
Pathologist Kenneth Thomson said in order for her to gurgle, Laniet would have had to been still alive. "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."
He said Laniet had inhaled blood, indicating she had continued breathing for some period after being injured.
Victorian pathology professor Stephen Cordner said Laniet may have been able to survive the three shots, and continue breathing for a period afterwards. He could not be sure how long, but said it was reasonable to suggest it would be minutes rather than hours.
Home Office forensic pathologist Dr Robert Chapman said it was possible Laniet survived for a matter of minutes after the three shots, and continuing respiration with blood in her airways created a gurgling or snoring noise.
THE 111 EMERGENCY CALL
The ambulance officer who took Bain's 111 call described it as "unusual" because Bain was able to give him basic information. Thomas Dempsey said it was easy to get Bain's telephone number, address, name and what happened.
He said in his experience of answering hundreds of 111 calls from people who are "overwhelmed by a situation", callers often find it difficult to give simple information.
The defence said they would call a witness on "voice stress" but that did not materialise.
WHO WAS ROBIN?
Robin has been described by friends and colleagues as a loving father and caring school principal, who was reluctant to hurt even insects because he felt that "everything has a right to live".
The defence painted Robin as a deeply depressed man who committed incest with his daughter Laniet.
A friend of Robin's, Graham Letts, described him as a "very quiet, passive sort of gentleman".
Darlene Thomson told the court that she taught with Robin at the small, isolated school, Taieri Beach School, near Dunedin. She described him as very private, but "kind, gentle and very caring".
He was like a grandfather to the children, and took every possible opportunity to teach them something.
A friend of Laniet, who cannot be named, said Laniet was "nervous but happy" when they met in Dunedin's Octagon on Thursday, June 16, 1994 - four days before the killings.
The friend said Laniet told her she had quit being a prostitute and "that she was going home that weekend to blow the whistle on her being a sex worker ... and that she had been having an incestuous relationship with her father".
Mr Wilden said Robin was suffering from "some sort of reactive depression or situational depression" which can be short-term.
He said he asked Mr Bain if he was getting medical help. Mr Wilden said he recalls Mr Bain "answering in the affirmative" but Mr Bain did not want to talk about it.
WHAT WAS BAIN'S MENTAL STATE LIKE?
With his fists clenched and eyes squeezed shut, Bain spoke about "black hands" taking away his family, and everyone dying as in the movie Schindler's List.
An aunt and uncle Bain stayed with after the death of his family said how he went into a state where his body was tense and his voice changed and he kept repeating the same jumbled phrases.
Jan Clark said of Bain: "He started to speak in a really slow, deliberate way. His words were almost as though they were being dragged out of him. He started saying 'black hands', and that they were taking him away, 'black hands' ... and just repeated this over and over."
Forensic psychiatrist Dr Brinded said Bain was not suffering from a mental or personality disorder in the months after the killings.
"Bain was extremely distressed at times during both interviews and at times quite difficult to interview," Dr Brinded said.
He said Bain was suffering from acute stress reaction and in time that can develop into post-traumatic stress disorder.