Dean Boucher and Mark Lange have been granted a new trial after five years of appealing their joint murder convictions.

The three-judge panel of the B.C.-Yukon Court of Appeal made it clear in their comments and questions to the assembled lawyers that they saw at least some of the same flaws in the original trial as pointed out by the defence lawyers.

Justices David Frankel, Mary Saunders and Elizabeth Bennett did not explain their decision to order a new trial today, but will provide written reasons in the coming weeks.

In a marked departure from his last Yukon Court of Appeal appearance, Boucher arrived in Courtroom 1 of the Whitehorse courthouse Monday armed with a stack of documents and accompanied by three lawyers.

Beside him sat the lawyer for Lange, the man who – with Boucher – was convicted of murdering Carcross resident Robert Olson in December 2005.

The two men both appealed the convictions shortly after a supreme court jury found them guilty in August 2006.

Boucher claimed at least one of the jury members was biased against him, and Lange argued the judge did not properly instruct the jury.

It was the judge's instructions which were at issue Monday and today, as two court-appointed lawyers took to the podium to deconstruct what they say was a deeply flawed set of supposed facts and instructions given to the 12-person jury by Justice Leigh Gower of the Yukon Supreme Court,

The lawyers, Jenny Cunningham and Richard Fowler, are not technically working for Boucher; instead, they are what's known as amici curiae, or friends of the court, and are tasked with making the complex legal arguments behind Boucher's appeal.

Cunningham was named as Boucher's lawyer last July after the 48-year-old man appeared in the court of appeal completely unprepared to argue his case last spring.

Knowing that Boucher was self-represented, the three court of appeal judges had reviewed the transcripts from the original trial and found several potential errors of law or process which could possibly prompt a retrial.

They appointed Cunningham, but after half a year of working with Boucher, she applied to be removed as the counsel of record. Justice Ron Veale of the supreme court then named her amicus curiae, meaning she still has to argue Boucher's case, but she no longer has to consult him or take his instructions.

She is assisted by Fowler, a Vancouver-based lawyer who has argued a number of murder appeals in the territory, and represented Karen Rodrigue in her failed retrial for the murder of Gerald Dawson.

Justice Gower made a number of serious errors, the two argued. First, he called Lange's statements to police "evidence” when he was describing their usefulness to the jury; the judge also said Lange's statements could be used to determine Boucher's actions and state of mind.

But statements are not evidence, Cunningham said, and they should only have been used to decipher Lange's case.

Cunningham also slammed the decision to permit a lengthy cross-examination of Boucher by Lange's then-lawyer which mentioned at least 10 incidents of violence which Boucher was never convicted of.

Many of the allegations were made from police reports and never resulted in any charges, yet they all served to unfairly smear Boucher's character, she said.

The cross-examination was "meaningless” to Lange's defence, but "very prejudicial” to Boucher's, Cunningham argued.

The court of appeal only hears arguments on points of law; it does not hear witnesses or accept new evidence, although it can allow new evidence in a retrial.

Karen Wenckebach – Lange's lawyer – asked the judges to order a new trial and allow new evidence, namely the fact that Boucher stood up after he and Lange were pronounced guilty and said he was responsible for Olson's death.

He has since recanted that admission.

Fowler's arguments delved into the deeper recesses of the law, and focused on the complexity of the legal questions the jury had to untangle.

The jury was not properly instructed on how to determine Boucher's state of mind and then relate that conclusion back to the question of manslaughter versus murder, he said.

The jury was told to look at Boucher's "word and conduct” before during and after the beating which led to Olson's death, Fowler said, and use that to determine his state of mind "at the time”.

But what exactly "at the time” meant was never properly explained, he argued, and may actually have been impossible to explain given the complexity of the narrative.

Furthermore, Fowler said, the jury was faced with no fewer than half a dozen different ways for each man to be legally responsible for Olson's death, including aiding and abetting, accessory, common purpose, and prior knowledge.

"How could any jury comprehend all those different things?” Fowler asked.

Lange and Boucher were charged with murder after Olson's body was found dumped in Wolf Creek.

The men admitted to beating Olson, stealing art from his Caribou Hotel in Carcross, taking his truck and dumping his lifeless body in the creek.

Each man blamed the other for Olson's death, however.

They were both found guilty of second-degree murder and sentenced to life imprisonment with no chance of parole for 18 years in Boucher's case, and 10 years in Lange's.

Several of Boucher's family members were in the courtroom Monday and today, including his three young sons.

Now that a new trial has been ordered, Boucher will remain at the Whitehorse Correctional Centre, where he has been since Monday.

Lange will be brought up from the federal penitentiary where is serving his sentence.

The men will likely have to remake their pleas, because both men took back their admissions to manslaughter during the trial.

No date has been set for their next court appearance.