A gun-packing ex-preacher who uses a wheelchair shot and killed a fellow retired religious leader at a Chicago senior center on Monday morning, officials said.

The unidentified gunman allegedly shot the deceased man in the face, killing him, CBS reported. Police said the gunman fired one shot, and then moved closer and continued shooting at the Senior Suites of Rainbow Beach.

No charges have been filed yet, but Chicago police have the accused gunman in custody.

Several residents identified the dead man as Allen H. Smith, 80, WGNTV reported.

The men frequently argued, CBS reported, and WGNTV said the two were heard to be arguing before the shooting.

“That’s mostly what they talked about, was religion,” Jamie Weems, who knew both men, told CBS. “So I’m pretty sure that has something to do with it.”

Despite their verbal altercations, neighbors said the two were friends, CBS reported.

“We are deeply saddened by this event, as the health and safety of all of our residents is and always will be our top priority,” the housing complex said in a statement.