ST. LOUIS • The mother of a man fatally shot by an undercover St. Louis police detective in 2010 has sued in federal court here, alleging the officer continued to fire as her son lay on the ground dying, then planted a gun on him to claim the use of deadly force was justified.

Normane Bennett, 23, was shot June 25, 2010, in an alley behind the 3900 block of Sherman Place after he fled from police who tried to arrest him and others for alleged drug activity.

Police at the time said that Bennett's family attacked officers, allowing him to flee, and that Bennett pulled a revolver from his pants and pointed it at the detective chasing him. A police report says the Smith & Wesson revolver was later recovered about four feet from Bennett's body. The department never released the detective's name.

The civil suit filed Thursday by Mary Barnett, Bennett's mother, identifies the officer as Detective Marc Wasem. It claims Wasem fired seven shots at Bennett, five of which struck him, and some of which were delivered as Bennett lay on the ground dying.