In October, Cody Haevischer and Matthew Johnston were found guilty of six counts of first-degree murder after six people were executed in a Surrey, B.C. high rise.
However, the two immediately launched an unusual type of legal proceeding, asking to have the verdict set aside.
They say there was an abuse of process because of alleged misconduct by several RCMP officers investigating the killings. Lawyers also say the two were treated inhumanely by the justice system during their pretrial incarceration.
Crown prosecutors concede mistakes were made in the case, but they argue those problems didn't have a material impact on the trial.
Prosecutors also told the judge that setting aside first-degree murder convictions would be a grossly disproportionate response to allegations of police misconduct.
Four of the victims were involved in the drug trade. Two others, a fireplace repairman who happened to be in the suite, and a neighbour were also shot at point blank range.
Despite the convictions, lawyers for Haevischer and Johnston say the investigation was deeply flawed and their clients deserve to be set free.
They say RCMP officer Derek Brassington allegedly had sex with one of the potential witnesses in the case. Brassington is now facing criminal charges.
Three other officers are also accused of various improprieties, including sexual contact with potential witnesses, making inappropriate comments about the investigation and fraudulently claiming overtime.
The defence says it all adds up to a pattern of misbehaviour by the RCMP, which should lead to the convictions being set aside.
Eileen Mohan, the mother of one of the Surrey Six murder victims — bystander Chris Mohan — said she was stunned to hear of the allegations of police misconduct, and that she would be devastated if the convictions end up being overturned because of it.
"I would probably have a heart attack if they walked free; that's how emotionally involved I am," she said.