Officials did not say how many shots were fired by the officer, 28, who has three years of law enforcement experience. He was the only officer at the shooting.

Ballard collapsed in an alley behind the 4100 block of Lee, where he was pronounced dead. He lived in the 7400 block of Chandler Avenue in Country Club Hills.

Three others who fled the stolen car ran off and were being sought Tuesday.

St. Louis County Police Sgt. Shawn McGuire said that neither the officer nor his police car was equipped with a camera. A pilot program to equip some county officers with body cameras has ended, and no county police cars currently have dashboard cameras.

Department policy allows civilians to ride with officers as long as they are older than 17 and have been approved by the commander.

Two St. Louis city police officers on their way to help with the pursuit were injured when their Chevrolet Tahoe collided with a Chrysler 300 at Union Boulevard and Lillian Avenue, just north of Interstate 70. Two occupants of the Chrysler were also hurt. Police said none of the injuries was life-threatening.