Karam said he has been working full time on the case, and said cabinet guidelines which were used in the decision on Bain's compensation were "contrary to justice and breached the common law of New Zealand".
"It is a myth that the criminal justice system is infallible and cant get it wrong."
Karam said Bain "reluctantly but pragmatically" accepted the $925,000 ex gratia payment.
"The compensation regime is in need of complete makeover to depoliticise the process and make it fair for all."
Karam said Bain would've accepted "anything" when he was acquitted in 2009, as long as he received a "decent apology".
"He wanted what Teina Pora was proud to get, instead he got a process that was absolutely stacked against him."
Karam felt Prime Minister John Key shouldn't have been "poking his nose into inquiries".
"David's been fighting an uphill battle against a system that is political.
"Its over. It's quite a lot of money but it's been such an ordeal that the amount of money now under all circumstances is a rather bittersweet pill to accept. But he, his wife and I am grateful."
Reflecting on his support of Bain, Karam said the case had "taken it's toll".
"I wouldn't say I was running out of steam but I'm not getting any younger.
"David's unquestionably like one of my family. There's one or two things I might change about the way I did it but having been confronted with what i was confronted with I would not change everything, as tough as it's been."
He said the fight was "unquestionably worth it".
"It's been enrichening in many ways but at the same time it has been very destructive."