Authorities said they were also investigating whether Melissa Merritt, 33, and Christopher Fattore, 36, who were taken into custody in Nova Scotia and charged with first-degree murder, were responsible for the death of her ex-father-in-law, the Toronto Star reported.
Merritt and Fattore are charged in the 2013 asphyxiation of Caleb Harrison, 41, of Mississauga, Ontario, and the 2010 asphyxiation of Bridget Harrison, 63. Both died in the same house, as did William Harrison, 65, whose death in 2009 had previously been attributed to natural causes.
Caleb Harrison had custody of the two children he had with Melissa Merritt. The two were married from 2003-2005.
Court records show he was convicted of domestic assault in an incident that occurred while they were married and was found guilty in 2008 of impaired driving causing death and three counts of impaired driving causing bodily harm in a car crash that killed a cab driver.
Bridget was a retired teacher and Toronto District School Board official. William worked in management for a grocery chain. They had adopted Caleb in the early 1970s.
Merritt, the daughter of a retired Toronto police officer and brother of a current officer, has two more children with her common-law husband Christopher Fattore, the Star said. Police said the children, who were with their mother when she was arrested, are safe.