The man charged with three counts of first-degree murder in the triple homicide in the Shawinigan area of Quebec on Wednesday knew all of the victims, police say.

Sylvain Duquette, 51, is accused of slaying Denise Hallé, Janet Lauzon-Toupin and Jocelyne Pellerin. 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.

According to Sûreté du Québec Sgt. Christine Coulombe, Pellerin was killed at a home in the municipality of Saint-Mathieu-du-Parc. Hallé and Lauzon-Toupin were then killed at a home on Lac-Marchand Street in Shawinigan's Saint-Gérard-des-Laurentides neighbourhood. Both homes were set on fire after the slayings.

Police said the victims were 56, 61 and 70 years old. Police have not said how the women were killed.

Quebec provincial police say two of the three female victims were killed Wednesday at this home in Shawinigan. (Charles Contant/CBC)

Duquette appeared in court in Shawinigan, located about 170 kilometres northeast of Montreal, this afternoon. He has been ordered not to have contact with his father, who was injured and is in hospital in stable condition.

A neighbour and a family friend have told CBC News that one of the victims is Duquette's sister-in-law.

It was one of the victims who contacted police using 911 to alert authorities to what was happening.

Duquette was driving a stolen vehicle when he was arrested at a gas station in Shawinigan, Coulombe said.

Police were at this gas station in Shawinigan this morning as part of an investigation into the triple homicide. (Maude Montembeault/Radio-Canada) An Irving gas station in the north end of Shawinigan was cordoned off Thursday morning. A white SUV, abandoned and with its doors open, remained at one of the pumps.

People at that scene told Radio-Canada that a gun, bullets and kitchen knives were on the ground near the vehicle.

Duquette is expected back in court on April 13.

Suspect was living with victim

Neighbour Caroline Lamarre said one of the women who was killed had been married to Duquette's brother, who recently died.

Caroline Lamarre is one of the victim's neighbours. She said the woman was always there when someone needed her. (Radio-Canada) The woman was a caring, giving person, Lamarre said.

"You didn't have to ask her anything. She would do it for you," she said.

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, Lamarre said.

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.

'This is shocking'

Family friend Michel Grenier said he has known Duquette and his sister-in-law for years, and that he is shocked by the events.

"I didn't go to work today. I didn't sleep last night," he said.

"It's inexplicable. I can't understand it."

Police say the suspect knew all of the victims, aged 56, 61 and 70 years old. (Josée Ducharme/Radio-Canada)

International Trade Minister François-Philippe Champagne, who represents the riding that includes Shawinigan, called the deaths a tragedy.

"This is shocking for a small community like ours," he said on his way to a cabinet committee meeting Thursday.

Champagne, as well as Quebec Public Security Minister Martin Coiteux and Lise Thériault, the Quebec minister responsible for the status of women, offered their condolences to the victims' families.