Pennsylvania fire officials are still investigating the cause of a house explosion which left five people, including a child, dead and several other homes damaged, officials said Monday.

The Allegheny County Fire Marshal’s Office is investigating multiple possibilities, including the homeowners having “hot water tank issues,” Plum Borough and Allegheny County officials said in a news release.

“The tank was located in the basement of the home,” county officials said.

Around 10:20 a.m. Saturday, Allegheny County officials received 911 calls reporting a house explosion in Plum, Pennsylvania, about 20 miles east of Pittsburgh, with “multiple injuries and several houses on fire,” Allegheny County officials said in a statement provided by the Plum Police Department. 

First responders said there were people trapped under debris, two houses on fire, multiple houses damaged and it appeared “as if one house had exploded,” authorities said.  

“There are three structures destroyed and at least a dozen more damaged in some way,” authorities said.

5 people killed in the explosion, 3 injured

Plum Borough Police Chief Lanny Conley said four adult bodies and a child were recovered shortly before 10:30 a.m. Saturday, The Associated Press reported.

Three people were taken to area hospitals, including one who was in critical condition and two who were treated and released. The names of the victims were not released. 

“This is certainly a sad, sad day and a sad time, for not just the folks in Plum but all the folks in the community and in this region,” Allegheny County Executive Rich Fitzgerald said, AP reported.

‘It looks like a war zone,’ neighbor says

George Emanuele, who lives three houses down from the home that exploded, said he and a neighbor went to the home after the explosion and dragged a man laying in the backyard away from the scene, he told the Tribune-Review. 

Rafal Kolankowski, who lives a few houses away, said the explosion broke the windows in his house and knocked him and his wife to the ground, he told the Pittsburgh Post-Gazette. 

“It’s just tragic, I mean, it looks like a war zone — it looks like a bomb hit our neighborhood and it’s just unfortunate,” Kolankowski said. “I was just with some of the neighbors yesterday, right, and now this happens.”

Contributing: The Associated Press