The fire erupted Monday in a detached home in the small community, located about 500 kilometres north of Montreal.
The car, a blue Honda Civic that had been reported stolen, was found in a wooded area near Havelock, Que., near the Quebec-U.S. border.
The suspect, Justin Bresaw, remains the subject of a Canada-wide arrest warrant.
Bresaw was seen near the Amos home before the fire started. He rented a room in the basement of the home in Amos, police said.
The 35-year-old man was last seen on Tuesday in the Ottawa area.
Bresaw is described as white, five-foot-seven, about 170 pounds and was last seen wearing a red sweater with long sleeves, work shoes and a black backpack.
A video of the blaze engulfing the structure was posted on YouTube. The bodies were discovered after emergency crews extinguished the flames.
The names of the victims have not been released but they are believed to be two men, aged 56 and 71, and a 61-year-old woman.