The discovery of the family was made in Woodstock midday Monday when an Ontario Provincial Police officer stopped by to see why Constable Laurie Hawkins hadn't shown up for work, the London Free Press reported.

The 41 year-old woman had only faint vital signs, and was resuscitated, but her 40-year-old husband Richard, a 14-year-old daughter and 12 year-old son didn't respond to rescue efforts, police said.

Hawkins was airlifted to Toronto General Hospital, where she was in critical condition Tuesday, the Woodstock Sentinel-Review reported.

Sources told the newspaper the children had not been at school since Thursday, and neighbors said they hadn't seen the family for days, the paper said.

Firefighters opened all the windows of the house and used exhaust fans to allow for an inspection of the heating system, the suspected source of the odorless and deadly carbon monoxide gas, police said.