BIRMINGHAM, Ala. (AP) — A mass shooting killed four people and wounded 17 others in a popular nightlife area in Birmingham, Alabama, with many of the victims caught in the crossfire, police said Sunday. Police Chief Scott Thurmond said at a news conference that authorities believe the intended target was among the dead and that the shooting may have been “a hit” conducted in exchange for payment. Investigators believe the other victims were caught in the crossfire and that there were multiple shooters. More than 100 shell casings were found at the scene. The shooting happened shortly after 11 p.m. Saturday in Five Points South, a district filled with entertainment venues, restaurants and bars that is often crowded on weekend nights. Thurmond said multiple suspects pulled up in a vehicle, got out, fired shots, got back in the vehicle and fled. Police said officers found two men and a woman on a sidewalk with gunshot wounds and they were pronounced dead there. An additional male gunshot victim was pronounced dead at a hospital, according to police. By early Sunday, after victims began showing up at hospitals, police had identified 17 people with injuries, some of them life-threatening, Officer Truman Fitzgerald said in an email. Authorities were asking for the public’s help for tips as they searched for the shooters. This story has been corrected to lower the number of injured to 17 from 18, based on amended information from the police.  Associated Press writer Jonathan Mattise in Nashville, Tennessee, contributed to this report.