The fire roared out third-floor windows on Carteret Avenue in Trenton on Saturday just before 7 p.m. as firefighters climbed onto a neighboring roof. Inside, other firefighters reported that the structure collapsing around them.

When it was over, two 20-year-old twin brothers had died, trapped on the third floor by the raging fire that reached three alarms. Two others in the house had escaped, one jumping from a window, officials said. Four firefighters were hospitalized.

The Red Cross of New Jersey reported helping nine people from four families who were displaced from the fire.

Sunday afternoon, Trenton spokesperson Timothy Carroll said all four firefighters had been released from Capital Regional Medical Center, with one being cleared to return to duty.

The cause of the fire at 834 Carteret Ave. was still under investigation, and county and state officials are assisting, as are members of Trenton’s police, health, and inspections departments, he said.

One firefighter had sustained burns and the other three sustained injuries due to the structure collapse, officials said. Their conditions were stable at time of transport, according to Trenton Fire Director Kenneth M. Douglas.

“I am praying for this family who lost two sons tonight. This is heartbreaking and we will do everything we can to support to get through this,” Mayor W. Reed Gusciora said, who spoke with firefighters at the scene Saturday evening.

June Davis, identified as the owner of the property by 6ABC told the station, “Every bone in my body is hurt right now for those kids.”