EDMONTON—Married for 57 years, they were kindred spirits and called each other darling.

Lyle McCann, 78, was known for his patience, a retired long-haul trucker who liked to play cribbage and watch curling on TV. Marie, 77, could whip up a five-course family meal and fill a room with her laughter.

Bret McCann has a recurring nightmare of his parents’ death — how one of them was killed first while the other had to watch in horror knowing he or she was next.

But he doesn’t know the details of what happened on July 3, 2010, the day his parents were slain after they left their Edmonton-area home on a camping trip to British Columbia.

Their burned-out motorhome and a vehicle they had been towing were discovered in the days after they vanished.

Their bodies have never been found.

"The one individual who knows where my parents are has said nothing for this whole time," Bret McCann told a sentencing hearing Monday.

"Travis Vader, where are the bodies of my parents?"

Justice Denny Thomas convicted Vader earlier this year of manslaughter. The judge concluded Vader was a desperate drug addict who had come across the seniors in their RV and killed them during a robbery.

Court heard that Lyle McCann’s bloodstained ball cap was found with a bullet hole in the couple’s SUV. DNA that matched Vader’s was also on the hat and his fingerprint was on a can of beer in the vehicle.

A friend testified Vader was broke, yet showed up flush with cash and driving an SUV that matched the one owned by the McCanns the day they disappeared.

The defence argued that the DNA evidence was sketchy, that witnesses had lied and that — with no bodies and no murder weapon — there is no real proof the McCanns are dead.

Vader, 44, sat expressionless in the prisoner’s box as victim impact statements from several McCann family members which painted a picture of an adoring, gentle couple were read in court.

Bret McCann recounted how his family put up posters and billboards, raised reward money and organized searches for his parents when there was still hope they were alive.

It’s still important that their bodies are found so they can be properly buried, he said, and he plans to attend every court hearing and parole date in the future to demand an answer.

"Vader has shown no sign of acknowledging that he even caused the death of my parents. He shows no remorse," McCann said.

"We will never forget and I will never forgive what Travis Vader has done."

Outside court, he told reporters that he might be able to forgive Vader if he revealed where the bodies are.

Vader, who did not testify during his trial, is to take the stand this week, said his lawyer Nathan Whitling. The defence has said it will ask the court to take into account abuse Vader allegedly suffered while in custody. Vader has filed lawsuits claiming mistreatment by guards and alleging malicious prosecution.

The defence is asking for a sentence between four and six years. The Crown wants a life term, but has not yet addressed parole eligibility.

Bret McCann called the defence request absurd.

"He’s killed two people in a robbery with a firearm, covered it up, lied about it for years," he said.

The case has been full of twists and turns since the beginning.

The RCMP was criticized early in the investigation when documents inside the burned motorhome linked it to the McCanns, but officers didn’t begin searching until five days later when the couple didn’t arrive in B.C.

Vader was quickly named a person of interest and later a suspect, but it took two years to charge him with first-degree murder. And just before his trial was to start in 2014, the Crown stayed the charges because RCMP hadn’t disclosed all evidence to lawyers.

The charges were later reactivated and, although Thomas acknowledged police mistakes and a slow court process, he denied a defence request to toss the case.

Thomas also made a mistake during the trial when he used an outdated section of the Criminal Code to convict Vader of second-degree murder. He refused to grant a mistrial and substituted the verdict with manslaughter.

The defence has said it will appeal.