It asks that the application be heard Oct. 3, when the judge is to set a sentencing date and determine if Vader should undergo a psychiatric assessment.

Legal experts say Justice Denny Thomas made a major error in the verdict by referencing a section of the Criminal Code that is no longer in effect.

Section 230 allows for a murder verdict if a wrongful death occurs during the commission of another crime such as robbery, but in 1990, the Supreme Court ruled the section unconstitutional.

However, it has never been repealed and remains in the Criminal Code.

Thomas’s ruling was broadcast live from Court of Queen’s Bench, a first for an Alberta criminal trial, but it quickly led to criticism of the ruling.

"This honourable court’s two guilty verdicts respecting an offence which does not exist at law constitute nullities," says the defence application.

It adds that the judge should not be allowed to proceed with sentencing or reopen the trial and impose a guilty verdict of manslaughter.

Bret McCann has said that despite the legal twist, he was happy to hear the judge rule Vader was responsible for the deaths of his parents.

The defence had argued that someone else may have killed the McCanns, who were both in their late 70s. It was also suggested they might not even be dead.

Their bodies have never been found. Their burned-out motorhome and SUV were discovered in the bush west of Edmonton days after the couple left on a trip to British Columbia.

Thomas ruled that Vader was a desperate drug addict who came across the couple and killed them during a robbery. The judge said there was no evidence to show Vader planned the killings.