Mario A. King was 38 and lived in East St. Louis, Illinois when he died from a fatal shooting on January 21, 2017. The shooting occurred in a neighborhood described as having high crime rates, and local police treated the death as a violent homicide.

The East St. Louis Police Department opened an extensive investigation. Investigators identified and questioned several suspects over time, pursued intermittent leads, and re-examined evidence, but the case has been hampered by a lack of immediate witnesses and limited concrete evidence. There were occasional arrests and charges in later developments, yet those did not produce a clear resolution.

The community held vigils and memorials for King while his family sought answers and closure. Anyone with information about Mario King or the January 21, 2017 shooting in East St. Louis is asked to come forward.