Man found not guilty of killing common-law spouse nearly 6 years after her death

After years of legal proceedings, a man has been found not guilty of killing his common-law partner and setting fire to their mobile home in Boyle, Alta.

Mario Bernier, 60, was charged with second-degree murder in the death of Melissa Lyne in September 2020, about nine months after her body was discovered on Dec. 18, 2019, in the burned wreckage of the home they shared.

Bernier's trial took more than two years to finish, with evidence spread across separate weeks from early 2023 to June 6, 2025, when Court of King's Bench Justice Shaina Leonard gave her decision.

Part of the reason for the protracted case was the fact that the murder trial was conducted in French — a rarity in Alberta.

At one point, Bernier tried to switch to an English trial, but the judge said Bernier wouldn't be able to adequately understand what was happening in court without an interpreter.

With most witnesses testifying in English, translators were required to interpret between the two languages throughout the trial.

But nearly six years after the incident, the judge concluded that Crown prosecutors didn't prove beyond a reasonable doubt that Bernier caused Lyne's death.

Bernier was acquitted on all three charges he faced: second-degree murder, arson and indignity to human remains.

Bernier found in Saskatchewan after the fire

The judge's decision, which was written and delivered in French, says there are too many unknowns to make a firm conclusion about what happened to Lyne.

The court heard that Lyne was planning to leave Bernier, and some of her friends and family members were helping her make a plan to move to B.C., where her brother lives. She told at least one person that she felt the relationship was abusive.

Lyne tried to leave on Dec. 7, 2019, but she was pulled over just after midnight by RCMP in Wabamun, Alta., a hamlet west of Edmonton, about 160 kilometres southwest of Boyle. Her car was impounded due to her blood alcohol concentration levels, and Bernier picked her up and brought her back to Boyle.

Ten days later, around 5:30 a.m. MT, a man called to report a fire at Lyne and Bernier's mobile home. Bernier and his vehicle were gone, but Lyne was found inside, her body severely burned. A kitchen knife was also found underneath her head.

An autopsy couldn't determine the cause of Lyne's death. The medical examiner didn't find a natural cause or any injuries such as stab wounds on her torso. But he concluded that there wasn't evidence of smoke inhalation, suggesting she was probably dead before the fire started.

Bernier was found the day after the fire in Chamberlain, Sask., a village about 80 kilometres northwest of Regina, after a truck driver called RCMP about a man with blood on his clothes asking for water.

Bernier had two large cuts on his arms and admitted he'd intentionally injured himself. He was taken to hospital in Regina, where he told two psychiatrists that his partner had left him.

Police interviewed Bernier over two days in September 2020 — roughly nine months later. He told them that, the night before the fire, he and Lyne were drinking heavily and had a physical altercation, during which he had to hold Lyne back from getting in her car and driving while drunk.

Bernier said he couldn't remember everything that happened, but told police that he and Lyne both fell when she tripped on a carpet, and she fell on a coffee table.

He said he tried to give her first aid, but passed out. When he woke up, she was cold and there was smoke in the home. At that point, he said he left and drove away.

Not guilty on all 3 charges

Crown prosecutors argued that Bernier's version of events was false, and that his sense of guilt was demonstrated through not calling for help, and fleeing the province and attempting suicide.

But Leonard found there are too many unanswered questions to determine what happened between Bernier and Lyne, and to prove he started the fire.

The pair were both smokers, but a fire investigator testified that the fire was a result of arson and didn't have a "smoldering" source he would expect to see if cigarettes were the cause. But in her decision, Leonard said she found issues with the investigator's analysis, including a lack of documentation to support his conclusions.

The judge found that, in light of available evidence, it's possible that Lyne's death was an accident and, after finding her dead, Bernier ran away in a state of despair.

The Crown, she said, hasn't proven the theory that Bernier killed Lyne — under circumstances that would constitute either murder or manslaughter — then intentionally set fire to their home to cover up the crime.