CHICAGO -- Part of a ceiling has collapsed onto a crowd of concertgoers at a Chicago nightclub, injuring four people.
Chicago police say a piece of the ceiling fell around 1:30 a.m. Saturday at the Concord Music Hall in the Logan Square neighborhood.
Three of those injured were hospitalized.
Witness Robert Foulks tells WLS-TV the accident sent dust into the air, and at first he thought it was from a smoke machine that was part of the show.
But he says it was soon clear something was wrong when security rushed to the area.
There was no official word on what caused the collapse.
Witness Ryan Chun tells WMAQ-TV that the sound system was so loud and bass-heavy that "it literally shook the ceiling down."