Toronto police have confirmed a third body has been found in the charred rubble of a townhouse destroyed by a massive blaze over the weekend.

The third victim was found Sunday evening, police said.

A handgun was also found and police are looking into whether the tenants of the home were shot before the house went up in flames.

Authorities said the bodies have not been removed from the debris because investigators are still combing the scene for clues on what sparked the blaze.

They believe the fire could have been deliberately set as part of a double murder-suicide plot.

"The theory is that two women were killed in some manner, perhaps a handgun, and then the adult has taken his own life," Det. Doug Sansom, from the homicide squad, told CTV Toronto.

The bodies need to undergo forensic testing before they can be identified but they are believed to a man, his wife and her elderly mother.

A young boy who also lived in the home was found wandering outside the burning building, located in the Lawrence Avenue and Don Mills Road area.

The superintendent of the housing complex told CTV Toronto someone knocked at his door at around 6 p.m. Saturday. When he opened the door, he found the boy whimpering for his father and clutching a note.

The note said, "This is my confession. There is a tape in the car."

Investigators have impounded the car and are currently investigating the contents of the tape.

The boy is now under the care of the Children's Aid Society but people close to the family told CTV Toronto he would likely be staying with his aunt who lives in Mississauga.

Police say they have responded to calls at the residence before for reports of domestic violence.

Neighbours said they've seen the woman run out of the house, crying.

"He was very violent, even when she was pregnant with the baby," said one neighbour.

Another neighbour said the man was away for awhile but had come back in the past year.

"That's the problem with these abusive relationships, it's kinda scary," he said.

Tenants who live in other units of the complex escaped unharmed.

The building was badly damaged in the blaze, which required about 100 firefighters and more than 20 trucks to extinguish the flames.

"It moved vertically through several units," Andrew Kostiuk, a Toronto Fire official, told CTV Toronto from the scene Saturday night.

Kostiuk called the fire "suspicious."

With a report from CTV Toronto's Austin Delaney