David Bain's first defence lawyer has emailed Justice Minister Judith Collins to say that, in his opinion, his former client had made a "damning admission" which in his view "shatters any suggestion of innocence".
The email was sent by disbarred lawyer Michael Guest to the Minister of Justice on September 10, just weeks after she received a report from retired Canadian Justice Ian Binnie saying Mr Bain was "factually innocent" and should be compensated.
Mr Guest's email became a factor in the decision to have Justice Binnie's report peer reviewed. On September 26, Mrs Collins wrote to retired Justice Robert Fisher saying Mr Guest's email, concerns from the police and her own issues "led me to consider that I need to proceed to this peer review".
Mrs Collins confirmed the link to the Herald, saying it added to concerns raised by herself, the police and the Crown Law Office.
Mr Guest claimed in his email he was prompted to contact Mrs Collins after reading reports Mr Bain had been found "innocent".
In a personal email, Mr Guest expressed his view to Mrs Collins which stated "finding that [Mr Bain] is innocent is not a correct conclusion".
Mr Guest claimed he was freed from client confidentiality because of an earlier waiver by Mr Bain. He said he was concerned because neither he nor his co-counsel had been interviewed by Justice Binnie as part of the inquiry.
Mr Guest repeated to Mrs Collins testimony he had given to the 1997 Police Complaints Authority investigators, later made available for Sir Thomas Thorp's 2003 report into Mr Bain's application for mercy.
The claims focus on whether Mr Bain was wearing his mother's glasses the weekend before the murders - the frame was found in his room and a lens in his brother Stephen's room.
Mr Guest said he was told by Mr Bain he had been wearing the glasses. He said Justice Binnie could have found a way to take a different view on the evidence about the glasses "but, in my opinion, it shatters any suggestion of innocence".
The email emerged through an Official Information Act request from Joe Karam, which was picked up by the Herald. Mr Karam said Justice Binnie had rejected Mr Guest's claims, including refusing to speak with the former lawyer because confidentiality had never been waived.
He said claims by Mr Guest also clashed with a letter the lawyer sent to Mr Karam after the first trial, in which he was "absolutely certain David is innocent" or had suffered a miscarriage of justice.
Justice Binnie was sent Mr Guest's email by Mrs Collins' office. He replied saying Mr Guest should "check with his former client" because his email "is based on the false premise that David Bain has waived solicitor-client privilege".
He said the issue was largely irrelevant because there was no evidence showing Mr Bain was wearing the glasses at the time of the murders.
Justice Binnie said he was "greatly reinforced in my conclusion about factual innocence" if Mr Guest felt free to speak and the glasses were "the most devastating thing he can come up with".
Mr Bain was convicted in a 1995 trial of the murder of five members of his family. The conviction was overthrown by the Privy Council. He was acquitted at a new trial in 2009.
Mr Guest was struck off in 2001 for lying to a client and taking $25,000 more in costs than he was entitled to.