Shots fired in Ferguson during Michael Brown memorial

Police approach a wounded man in a parking lot after a gunman exchanged fire with police during a demonstration Aug. 9 in Ferguson, Mo., to mark the one-year anniversary of the shooting death of Michael Brown.

St. Louis County Police and Missouri State Highway Patrol troopers stand guard as protesters march in Ferguson, Mo., on Aug. 9, 2015.

People come to the aid of a distraught woman after gunshots were fired near a protest in Ferguson, Mo., on Aug. 9, 2015.

Police take cover as gunfire erupts along West Florrisant Avenue in Ferguson, Mo., during a demonstration on Aug. 9, 2015 to mark the one-year anniversary of the shooting of Michael Brown.

Police officers respond after shots were fired during a protest march on Aug. 9, 2015 on West Florissant Avenue in Ferguson, Mo.

Police guard a strip mall along West Florrisant Avenue in Ferguson, Mo., on Aug. 9, 2015 during a demonstration to mark the one-year anniversary of the shooting of Michael Brown.