A 34-point list of issues attacking the case for David Bain's innocence was compiled by Justice Minister Judith Collins and sent to the former High Court judge she appointed to "peer review" the case.
The list was sent with her letter of instruction to Robert Fisher QC, who prepared a report which dismissed the finding of former Canadian Supreme Court Justice Ian Binnie that Mr Bain was probably innocent.
It has prompted Opposition parties to accuse Mrs Collins of bias and attempting to rort Mr Bain's claim for compensation, filed after he was found not guilty in 2009 of murdering his family. It was the second murder trial stemming from the 1994 murders - Mr Bain was convicted of murder at the first and spent 13 years in prison before the original verdict was quashed.
In November 2011, the retired Justice Binnie was appointed by former Justice Minister Simon Power to investigate the case. By the time Justice Binnie reported the following August 30, Mrs Collins was Justice Minister.
She had the report reviewed and then dismissed Justice Binnie's findings.
Her rejection led to Mr Bain putting the compensation bid on hold and filing court proceedings to get a judicial review of the case.
The Weekend Herald has learned almost 30 copies of the report were made in the week after Mrs Collins received it, and they were distributed widely - but not to Mr Bain's lawyers or supporters.
Police received a copy and prepared two rebuttals to Justice Binnie's findings. It is understood the Crown Law Office also received copies.
After having the report for 27 days, Mrs Collins, documents show, asked Mr Fisher to review the findings and "provide advice to me on whether or not you agree with his conclusion" of probable innocence.
She attached to the report a bundle of documents including the police critique, and a separately marked "Appendix B" - a list of 34 points marked "confidentially and legally privileged" criticising Justice Binnie. The document is not headed or signed, but is referred to in Mrs Collins' letter: "A synopsis of other concerns that have been conveyed to me is set out in Appendix B to this letter."
The top points directly criticise Justice Binnie, saying the language and analysis he used "may give rise to concerns that the judge has 'descended into the arena'." The term describes a judicial officer who has been captured by one side of a case.
The remaining 33 points highlight detailed points of argument from the case, likely to be known only by those with an indepth knowledge. Among the points are references to Crown submissions from the case - and claims made by the prosecution dismissed by defence witnesses.
Green Party co-leader Metiria Turei said Mrs Collins must explain where the unsourced briefing paper came from and the source of the information it contained. She questioned whether it was secret knowledge learned through Cabinet roles.
"If she has provided Mr Fisher with detailed information only she is privy to as Minister of Justice or Minister of Police there is a very serious conflict issue here ... . she has let personal bias get in the way."
Labour justice spokesman Andrew Little said the process for compensation and pardon needed to be lifted out of political office. "It's open to political abuse and I think that's what has happened in the Bain case."
A spokeswoman for Mrs Collins would only comment that "this matter is currently before the court".
The Bain file
• August 30: Retired Canadian Justice Ian Binnie sends his report to Justice Minister Judith Collins.
• August 31-September 6: Almost 30 copies of the report are produced and distributed.
• September 12: Police respond with a detailed list of issues.
• September 19: Police send a second, more detailed list of issues.
• September 26: Collins engages Robert Fisher QC, and sends "Appendix B" detailing her "concerns".
• December 13: Collins releases the Binnie report and Fisher's review, saying the original review is inaccurate and can't be used.
• July 31: Application for judicial review.