Roy A. Mickens replaces R.O. Ike, who resigned recently after a woman filed a sexual harassment claim against him.
Former East St. Louis Assistant Chief R.O. Ike speaks to reporters at the scene of a deadly crash in October 2012.
R.O. Ike had been with department since 1996.
Authorities not saying why assistant police chief was suspended.
Hit-and-run was about 12 hours after another fatal crash in East St. Louis.
Man stole police car after being ordered off a Metro bus for refusing to pay fare, police say.