The bodies of Nancy Samson, 44, and Benoit Daigle, 39, were found outside a private residence in Sainte-Croix-de-Lotbinière Saturday evening.
Investigators later discovered the body of Medora Godin, 13, along with her critically injured 11-year-old sister and an injured and unconscious 54-year-old man at a house in Saint-Isidore, some 70 kilometres away from the first crime scene.
Both the injured were taken to hospital. Police say the 54-year-old man is their main suspect.
Sûreté du Québec investigators believe he is the girls’ father and that Samson was their mother.
“It looks like a love triangle,” Sgt. Audrey-Anne Bilodeau told CBC News.
Bilodeau said it appears the suspect tried to take his own life.
She did not identify him since he has yet to be formally charged.
Jacques Gauthier, the mayor of Sainte-Croix, knows the family and said they had been through rough patches recently, but he thought the situation was improving.
“They had their problems in the past, but who hasn’t,” he said.
Autopsies on the three dead will be conducted this week.