The two women critically injured in a house fire in Chillum Sunday morning have died, and fire investigators now believe the blaze was sparked by an overloaded power strip in the living room, authorities said Tuesday.

The deaths of 36-year-old Simone Anne Munroe and 61-year-old Janet Assing-Macklin bring the death toll in the fatal fire to three, authorities said. Six-year-old Omari Noel, Munroe’s son and Assing-Macklin’s nephew, was pronounced dead Sunday, the same day the fire gutted his family’s home in the 2400 block of Griffen Street, authorities said.

The fire broke out just before 4 a.m., sparked by the overloaded power strip in the living room, authorities said. Neighbors reported hearing a loud bang, then saw smoke and flames shooting from the single-family home.

Noel’s grandmother was able to escape and bang on the windows, trying to alert her family that something was amiss, but her efforts were in vain, according to witnesses and fire officials. Firefighters had to pull Noel, his mother and aunt from the wreckage, all in grave condition.

Authorities have said previously the home had no working smoke alarms. Efforts to locate other family members were unsuccessful.