MISSISSAUGA, Ont. - The Special Investigations Unit says there are no reasonable grounds to believe any officer committed a criminal offence in the deaths of a woman and her son in a fire at a Vineland, Ont., home.

The police watchdog agency says two Niagara Regional Police officers were sent to the home on July 5, 2015, in response to a call about a domestic dispute and heard screams from inside when they arrived.

The SIU says the officers found a 50-year-old man standing in the living room beside his 73-year-old mother, who was in a wheelchair.

Within seconds of the officers entering the home, the man ignited gasoline that had been poured in the room, and when one officer attempted to rescue the woman, he slipped, fell to the floor, and his body caught fire. The officers managed to escape the burning home and extinguish the flames on the officer's body.

The man and woman died of acute smoke inhalation and carbon monoxide poisoning, while the officer who caught fire was hospitalized with severe burns.

SIU director Loparco says neither officer was in any way responsible for the fire that took the lives of the mother and son, and it is evident that they had no chance to intervene.