VANCOUVER -- Warning: Disturbing content.

A man has been found guilty of first-degree murder in the brutal killing of a Vancouver couple in 2017.

Rocky Rambo Wei Nam Kam first went on trial in September 2019, facing two counts of first-degree murder in the deaths of 64-year-old Dianna Mah-Jones and her husband 68-year-old Richard Jones.

Mah-Jones was a highly-respected occupational therapist at GF Strong Rehabilitation Centre. Her husband was retired and relied on a walker. Their bodies were found in their Marpole home on Sept. 27, 2017.

During the trial, Kam took the stand and testified he forced his way into the couple's house where, he said, he choked and stabbed Mah-Jones and also stabbed her husband and attacked him with a hatchet.

He told the court he did not know them and had no reason to attack them.

Kam's defence lawyer, Glen Orris, had argued his client believed he was in a video game at the time. Kam testified he used to play video games for up to 12 hours a day or more.

Orris argued Kam "could not appreciate in a real sense the real life consequences of his actions," and suggested the appropriate sentence was manslaughter.

The Crown argued the killings took planning and deliberation, and said items Kam testified he had purchased at a Canadian Tire two weeks beforehand, including a hatchet, were bought with the intent to kill someone.

Prosecutor Daniel Mulligan called Kam a "demonstrated liar" and said "the fact he did not state his motive does not mean he didn't have a motive."

While delivering her verdict, Justice Laura Gerow told the court there was no question Kam was the person responsible.

"Mr. Kam admits he killed them. As well, the DNA and surveillance video evidence proved beyond a reasonable doubt Mr. Kam was the killer," she said.

Gerow found the Crown had proved Kam had the intent for murder, and that both killings were planned and deliberate.

She noted Kam had no reason to harm Jones or Mah-Jones, and called his conduct "incomprehensible."

"He did not express any emotion about killing them, or express any remorse," Gerow said.

Gerow added she did not find some of Kam’s evidence credible, describing many of his answers as long and self-serving. She also found many of his explanations for his behaviour were improbable and not believable, including the reasons he gave for buying the hatchet and other items and why he was carrying those things around in his backpack.

Other than speaking quietly with Orris on occasion, Kam was silent throughout the proceedings, wearing a red prison outfit and a mask, his hair longer than at previous appearances. People watched from the gallery in physically-distanced seating, with tape blocking off sections to maintain spacing.

A first-degree murder conviction carries an automatic life sentence, with no chance of parole for 25 years.

The verdict in this case was originally supposed to be delivered on April 3, but was postponed following court closures due to the pandemic.

Sentencing is scheduled for June 18.