DETROIT (WWJ) - One of five Detroit firefighters that was injured by a collapsed roof during a call Thursday afternoon will remain in the hospital overnight.

Deputy Fire Commissioner Dave Fornell said the fire happened early Thursday afternoon, as firefighters were dousing the flames at a one-and-a-half story vacant house on near Vernor and Springwells on the city's southwest side.

"While they were in the building, the back end of the building collapsed. One fireman was trapped in the debris," Fornell said.

"So there were a total for three that were injured that were transported immediately," he said. "The folks went in there, got them out, and now we're going to be transporting two more; so there's gonna be a total of five injured in this fire."

Five firefighters were taken to the hospital and three have already been treated and released, while one firefighter who suffered burns will be treated overnight. The condition of the fifth firefighter that was injured was not clear.

Fornell said additional departments were called in to help tackle the fire, which started around noon. He noted that working on vacant houses can be exceptionally dangerous for firefighters.

Officials say the cause of the fire is suspected to be arson. A $5,000 reward is being offered for tips in the case.

The house on Whittaker off Vernor in SW Detroit where 5 @DetroitFire fighters were injured. Officials say this is the work of an arsonist and now a $5000 reward is being offered in the case. @WWJ950 LISTEN >> https://t.co/YNbPdRr9nN pic.twitter.com/oJCNidIEbF — Stephanie Davis (@sdaviswwj) October 3, 2019

"It's a call when you get to a fire," Fornell told WWJ's Rob St. Mary. "It's up to the officers on the scene to see if maybe they can get inside to to put the fire out. And in this particular case they did and they were knocking the fire down when the roof collapsed."

Fornell says charges against the suspected arsonist could be more severe because of the firefighters' injuries.

Anyone with information is urged to call the Detroit Fire Department arson tip line at 313-628-2900.