VANCOUVER -- After police officers left the room during a marathon eight hour interrogation, Rocky Rambo Wei Nam Kam spoke aloud in Cantonese, saying "I didn't kill anyone. How can I be sorry? I can only be sorry if I killed someone."

During cross examination at Kam's first-degree murder trial, Crown suggested that was an act for the camera. But the accused testified when he was questioned by police, he didn't think he had killed Dianna Mah-Jones and her husband Richard Jones in their Marpole home in September 2017.

Kam said in the weeks after the murders his "life didn't change at all."

"I go to bed with no problems, and I keep reading comic books and playing video games," he testified. "My behaviour, it’s not consistent with someone who killed two people."

Kam testified after speaking to a doctor he came to understand he did kill the couple, and described on the witness stand how he first spotted Mah-Jones unloading groceries from her car.

Crown asked him, "What was it about her that made you attack her?"

"I don't know," Kam responded. "I haven't figured out why Dianna Mah-Jones triggered me."

Kam described pushing his way into the house, strangling and then slicing the throat of the 64-year-old woman. And when her 68-year-old husband arrived home minutes later, Kam admits to stabbing him more than 100 times, telling the court: "I just keep stabbing, I have no idea where the knife is aiming."

Even though he was carrying two knives, a hatchet, twine and gloves, Kam insists the killings weren't premeditated, and he doesn't know why he did it.

Kam's lawyer has suggested his client was a suffering from a mental disorder and thought he was in a video game when he killed the couple. But so far on the witness stand, Kam himself hasn't said anything like that, answering all Crown's questions about his motive and state of mind with "I don't know."

Kam, who pleaded not guilty, testified after the murders he thought: "I know I'm not an immoral person” and “I don't understand why I didn't feel guilty about killing Mr. and Mrs. Jones."

Cross-examination is expected to wrap up Wednesday.