Five people were killed and one wounded in a shooting in an Oshawa home east of Toronto, local media reported.
The shooting happened around 0520 GMT on Friday. Police said four males and one female are among the dead, Xinhua news agency reported.
The wounded woman found inside the home was transported to the hospital in a serious but non-life-threatening condition.
The deceased victims are believed to be three adults and two teens, police media spokesman George Tudos said.
One of the dead is the alleged suspect, he said.
A husband and wife, who are teachers, have lived at the home with their four children for many years and recently returned home after spending time at a cottage, neighbours said.
Police said they were not looking for any more suspects and there were no safety concerns in the community.
Investigation into the shooting is underway.