RAYTOWN, Mo. (AP) — Authorities found a body Tuesday in the basement of a suburban Kansas City duplex where multiple people were injured in an explosion.

John Ham, a spokesman for the Bureau of Alcohol, Tobacco, Firearms and Explosives, told The Kansas City Star that the body will be taken to the medical examiner for identification once the Raytown building is secure.

About half the structure was reduced to rubble in Monday night’s blast.

Police said in a news release posted on Facebook that there were “multiple injuries reported” but didn’t provide any details on their severity or the exact number of people hurt. The release also said the cause of the blast was unknown.

Witnesses told KMBC-TV that two boys were conscious and alert when they were wheeled from the scene on gurneys. The station reported that a man also was injured and taken to a hospital for treatment.

The Missouri Fire Marshal’s Office is leading the investigation. ATF agents were assisting.

Ham and the Missouri Fire Marshal’s Office didn’t immediately return a phone message from The Associated Press.