A three-year-old toddler was inside the home on Lac-Marchand Street, in Shawinigan's Saint-Gérard-des-Laurentides neighbourhood, when the two women inside were attacked and killed, according to Radio-Canada sources.
Sylvain Duquette is accused of slaying Denise Hallé, 61, and Janet Lauzon-Toupin, 56. After the killings, the house was set on fire.
According to sources, the three-year-old managed to get out of the house safely and went to a neighbour's.
Duquette, 51, is also accused of crimes that took place at another home about one kilometre away in the municipality of Saint-Mathieu-du-Parc. He is charged with first-degree murder in the death of Jocelyne Pellerin, 70.
He is also accused of attempted murder with a firearm, the unlawful confinement of his father and Pellerin's partner, Claude Duquette, 80, and an arson-related charge.
That home was also set on fire.
The accused's father survived the attack and is in hospital in stable condition.
Duquette was living with his sister-in-law, but she asked him to leave because she felt she didn't have the means to support someone else, neighbour Caroline Lamarre told Radio-Canada.
Venting on Facebook
Days before the triple homicide, Duquette published a long post on Facebook expressing frustration with his living situation.
"My dad came by here, and he didn't even look at me or offer five dollars to help me knowing very well that tomorrow they are going to throw me out on the street like a filthy undesirable to make room for visitors and for friends coming to spend a week at my sister-in-law's where I live," he wrote on March 30.
People have been leaving flowers in honour of the victims outside the two homes.
"It is a weakness, in my book, to attack a woman for nothing. Make your decisions in life, but don't attack anyone who does not deserve to be attacked," said Belal Shidid, who described Denise Hallé as being "like a mother" to him.
The bodies of Denise Hallé, Lauzon-Toupin and Jocelyne Pellerin were removed from the residences of Saint-Gérard-des-Laurentides and Saint-Mathieu-du-Parc on Thursday evening.
On Friday, staff from the SPA Mauricie, the region's animal protection agency, picked up two dogs at the home of the accused.
Police officers continue to patrol the area to interview neighbours.
Representatives from the Centre for Victims of Crime are accompanying the officers to offer support to those who were close to the victims.