David Bain was convicted in 1995 of murdering his parents, Robin and Margaret, and siblings Laniet, Arawa and Stephen in their Dunedin home.
• Police to review Bain doco information
He was found not guilty in a retrial in June last year, after his defence team argued Robin Bain shot the other four family members before turning the gun on himself - with his motive being his incestuous relationship with daughter Laniet.
David Bain's lawyer, Michael Reed QC, last night said he was "absolutely disgusted" with The Investigator Special: The Case Against Robin Bain, which screened on TVNZ last night, and with what he described as inaccuracies and allegations made in it.
Documentary-maker Bryan Bruce went through evidence from David Bain's two trials concluding that, in his opinion, there was no evidence, forensic or otherwise, that Robin Bain killed his family.
He then raised the issue of defence witness Daryl Young, who told the jury at David Bain's retrial that when he met Robin Bain while selling him a photocopier for Taieri Beach School, Mr Bain had been speaking with a woman in his caravan, before coming out smelling of alcohol.
Mr Bruce said he had spoken to two people who contradicted Mr Young's story.
"In many ways, I think Robin was a victim of the 2006 Evidence Act which allowed in all the hearsay evidence against him and since he and his daughter are dead his reputation cannot be easily defended," Mr Bruce said.
"When our lawmakers look back at what we should learn from the Bain case, I would hope they will review the disclosure rules so that the defence have the same obligations to disclose as the prosecution."
Joe Karam could not be reached after the show.
Mr Reed said David Bain's legal team would consider what further action, if any, it would take today.
He said Mr Bruce had glossed over "lots" of evidence of Robin Bain's depression, and his motive for killing his family.
"I am disgusted by the fact [Mr Bruce] didn't spend one second in court, that he is challenging the jury and that he was disrespectful of the system and of the judge."
Dunedin woman Jan Clark, the sister of Margaret Cullen-Bain, declined to comment.
Police said they would make a statement today.
