A cardiologist is a possible suspect in the deaths of his two young children in what police said appears to be a double murder and attempted suicide in their home in the small Quebec community of Piedmont.

Municipal police arrived at the home in the Laurentian mountains, 60 kilometres northwest of Montreal, on Saturday morning and discovered the bodies identified by police as three-year-old Anne-Sophie Turcotte and five-year-old Olivier Turcotte. They had been contacted by concerned family members who hadn't heard from the father, police said.

They also found a 36-year-old man identified as the children's father whose name police wouldn't confirm. He was alive but needed medical attention for an apparent drug overdose, police said.

He was taken to the St-Jerome health and social service centre where doctors there realized the man was one of their colleagues, a cardiologist. Hospital director François Therrien confirmed the man was having marital problems with his wife, who is also a doctor at the hospital. The two have worked there for about six years.

"He was at work on Friday," Therrien said. "This is a human tragedy."

Doctors decided to transfer the man to a hospital in Montreal where he remains in stable condition. 

Gregory Gomez Del Prado speaks for provincial police.

"When we get the OK from his doctor, we'll interview and question him," said Sgt. Gregory Gomez Del Prado.

"I don't know exactly how it happens," said neighbour Gilles Poirier. "It's very sad."

Provincial police took over the investigation and returned to the scene on Sunday.

Autopsies on the siblings were expected to take place in Montreal either Monday or Tuesday to determine the cause of death.

Police say they have contacted the children's mother, who was on a ski trip.

With files from the Canadian Press