Ontario's Fire Marshal says delays in detecting a fire "contributed significantly" to the deaths of four family members trapped inside their burning home in a small town north of Toronto.
Ontario Fire Marshal Tadeusz (Ted) Wieclawek says by the time firefighters were called to the scene in East Gwillimbury last week, the home was fully engulfed in flames and the family's escape route was blocked.
Wieclawek says a preliminary investigation shows there was no smoke detector on the main floor and the one serving the second floor was wired through the main floor laundry room.
That's where Wieclawek says the blaze appears to have broken out, though forensic tests are still required to determine what started it.
He says smoke and flames then rose through a staircase to the second floor, where the four were trapped.
The victims of the fire were identified as Kevin Dunsmuir, 55, his wife Jennifer, 51, and their two sons Cameron, 16, and Robert, 19.
Authorities have said police and firefighters were unable to get the victims out of a second-floor bedroom, where they died.
Meanwhile, there are new questions about the response time of the East Gwillimbury volunteer fire service and why the Newmarket fire department was not called in under a mutual agreement pact.
Newmarket had a house of professional firefighters within a 10-kilometre radius of the fire.
The funeral for all four victims will be held on Friday.