Police said in a news release that police were called to the home at about 5:35 a.m. ET. Blackstock is about 30 minutes northeast of Oshawa.
The woman was pronounced dead at the scene and the man was rushed to a local hospital, before being transferred to a Toronto hospital.
The Durham police’s homicide unit is on scene, along with a forensic unit and the North Division Criminal Investigations Bureau.
Anyone with information is being asked to contact Det.-Sgt. J.J. Allan at 1-888-579-1520 ext. 5400.
Anonymous tips can be made to Durham Regional Crime Stoppers at 1-800-222-8477 (TIPS) or online at durhamregionalcrimestoppers.ca.