Martin Chambers was sentenced in 2003 after he was convicted in a scheme to launder millions of dollars for a Colombian drug cartel.
Then-RCMP investigator Bill Majcher worked undercover with the FBI on the sting that caught Chambers.
Chambers alleges Majcher was having an affair with trial judge Ursula Ungaro.
In documents filed in B.C. Supreme Court, Chambers claims the judge's ex-husband has now come forward, saying Ungaro admitted to committing adultery with Majcher.
Chambers also alleges Majcher and Ungaro discussed the case prior to sentencing over dinner at a Miami restaurant.
The documents allege that Majcher — no longer with the RCMP — has admitted to the affair, but claims it occurred after Chambers’ sentencing.
If there was an affair before the case ended, Chambers wants his sentence reviewed, reduced and perhaps to be returned to Canada.
Chambers’ lawyer, John Conroy, is asking the court to have the RCMP produce records to establish Majcher's timeline in Miami.
"If the judge had a relationship with the main witness in the case, prior to sentencing, then that would be inappropriate and improper and result in Mr. Chambers being re-sentenced," Conroy told CBC News.
"I think if you put yourself in the shoes of the person who is being sentenced, that would not be a fair and impartial sentencing."
None of Chambers’ allegations have been proven in court.
Majcher is now working in the finance industry in Hong Kong, while Ungaro is still serving on the bench in Florida.
Neither responded to CBC News requests for comment.