A Christian couple prayed for two hours over their dying son before calling an ambulance, a court heard on Wednesday.

An autopsy determined that Alexandru Radita, 15, from Canada, died from bacterial sepsis from complications due to starvation and untreated diabetes in May 2013. The court heard he weighed just 37 pounds at the time of his death.

His parents, Emil and Rodica Radita, had returned from church to find Alexandru not breathing. They are currently on trial and have been charged with first degree murder.

"They said they went to church at, I think it was after 1800 hours, and they came home at about 2000 hours and that's when the father said that he wasn't breathing, so they prayed and they didn't call EMS until sometime around 2200 hours," Shauna Mitchell, an investigator with the Medical Examiner's office, told National Post.

"The boy was extremely thin," Larry Pugliese, the first police officer on the scene, told the Court of Queen's Bench murder trial.

"I thought at the time maybe (he weighed) 20 pounds," he said. "When I looked at the boy my first instinct is he's dead."

Mitchell reiterated to the court that Alexandru "basically looked like a skeleton with skin" when she viewed his corpse.

"Emil said he had told Alexandru he needed to go to the hospital but he refused, he didn't like to go to the hospital because he had a bad experience when he was three years old," Pugliese said.

Pugliese said Emil confirmed that the boy had diabetes and there was insulin in the refrigerator, but he said that Rodica told him Alexandru simply had the flu.

Mitchell suggested to the court Alexandru could have stopped breathing before the couple even left the house to go to church.

The trial continues next week.