A mass shooting Saturday night left four people dead and at least 21 other people injures, Alabama police said.

The shooting happened shortly after 11 p.m. on Magnolia Avenue South in Birmingham’s Five Points South area, police said.

The shooting occurred outside club Hush where people were waiting in line outside the establishment.

Three people were pronounced dead at the scene and a fourth victim died later at UAB Hospital.

Investigators said they believe multiple shooters fired into a group of people.

“Rest assured, we are going to do everything we possibly can to uncover, identify and hunt down whoever was responsible for preying on our people,” Birmingham police officer Truman Fitzgerald said.

Fitzgerald said investigators are working with federal authorities and are seeking the help of the public to determine what occurred at the shooting.