Four children, including an infant, were killed, and their mother was badly injured in a house fire in Atlanta area Tuesday night, authorities said.

The fire broke out in a duplex house in Conyers Suburb, east of Atlanta. The bodies of all the victims -- three boys and a girl under the age of seven -- were found inside the home.

Conyers Police Department Maj. Mike Waters told WGCL-TV that “two adults and a 5-year-old boy were able to escape the home, but that the victims' mother had been taken to Grady Memorial Hospital with severe burns.”

The mother threw the five-year-old boy out of their second-floor window to save him from flames, and he survived. The children’s grandmother, who was present in the house during the fire, escaped unhurt.

The police arrived on the spot within seconds of the distress call and attempted to put off the fire with handheld fire extinguishers but were forced to back out by the flames, Waters told WGCL-TV.

Authorities were investigating the cause of the fire.