A couple who perished in a west Quebec house fire last week died of asphyxiation by carbon monoxide, according to an autopsy conducted in Montreal.

Corina Usher Hayward, 56, and Richard Henry Neil, 51, were found dead last week in their home at 3122 Ch. Wilson in the Municipality of Pontiac, near Highway 148 and the Ottawa River.

The two lived in the basement of the home and were unable to escape because of the smoke.

The owners of the home were able to escape and called 911 from outside after smoke filled their home.

Regional police MRC des Collines said Neil had a warrant for his arrest by police in both the Niagara and Sudbury regions for charges including breach of probation, but had said they didn't suspect foul play.

The autopsy results confirmed not only the time of death, but also that that there were no signs of violence on the bodies of either of the victims.

Results of toxicology tests will be released at a later date, police said Tuesday.

The cause of the fire is still not known.