The province's police watchdog has launched an investigation into the deaths of a 73-year-old woman and her 50-year-old son near St. Catharines, Ont.

Police were called to a home on Epp Street in the town of Lincoln at approximately 8:30 p.m. on Sunday.

The Special Investigations Unit (SIU) says shortly after the officers entered the home, a house fire broke out. According to one neighbour, he heard a loud explosion that rocked the area.

"All of a sudden, we heard this explosion – this big bang," Marty Wagenaar told CTV Toronto on Monday.

The SIU says the two officers were injured and were transported to hospital.

On Monday, a charred motorized wheelchair was spotted on the front lawn of the home.

Neighbours told CTV Toronto the 50-year-old man lived at the home with his mother. They also say they heard screaming and shouting prior to police being called.

The SIU and the Ontario Fire Marshal's office are investigating the incident.

A post-mortem has been scheduled for Tuesday.

The SIU is an arm's length agency that investigates reports involving police where there has been death, serious injury or allegations of sexual assault.

With a report from CTV Toronto's John Musselman