A three-year-old allegedly set fire to a home on Thursday that killed his mother, himself and twin siblings.

Fire investigators determined that three-year-old Trenton Delisle, who would have turned 4 next week, set fire to items in the living room of the family's mobile home, according to Maine Department of Public Safety spokesman Stephen McCausland.

The boy died along with his 28-year-old mother, Norma Skidgel, and his twin 2-year-old brother and sister, Mason and Madison Delisle.

The state fire marshal's office said in a statement that an investigation has determined Trenton Delisle lit the blaze when he "set fire to items in the living room" of the home.

State police spokesman Steve McCausland said the fire was likely started with a cigarette lighter. He said the nature of the items that the boy site afire was unclear.

Investigators also say there were no working smoke detectors inside - only one was found and the battery had been removed. The rear door to the mobile home also had been blocked by a large piece of Styrofoam, likely for insulation.

Skidgel's sister, Amy Bouchard, also lived at the home with her two children and extinguished a fire Trenton set - a Bible in the kitchen stove - earlier Thursday morning, police said. Bouchard and her children were not home when it caught fire.

The four deaths highlight the need to educate children about fire safety at a young age, McCausland said.

"This is a sad tragedy," he said. "Resources were available to assist him but were never utilized." Bouchard, according to Gibson, saw the fire from the nearby school bus stop and rushed back to the residence. Bouchard was taken from the scene to Cary Medical Center in Caribou, where she was treated for smoke inhalation.

"That was her sister," Gibson said softly. "She tried to save them.

"We are all taking this hard," the cousin added. "But we got to go one day at a time [and] it is a little better today. We are thinking about the good memories."

Norma Skidgel was a good mom trying to do the best she could for her children, Gibson said.

"Juvenile firestarters are a huge problem in Maine and there are resources available throughout the state to counsel, educate and treat children fascinated by fire," Thomas said.

Bouchard left the mobile home Thursday morning to put one of her children on a bus at a nearby stop and found the home ablaze when she returned, police said. She suffered smoke inhalation while trying to get back into the home and was treated at a hospital, police said.

An autopsy Friday determined Skidgel and the twins died of smoke inhalation, police said. Trenton's autopsy was still underway, police said. The four deaths brought the total number of fire deaths in Maine to 25 for the year, the most since 1993.