In the early hours of February 4, 1999, an unarmed 23-year-old Guinean student named Amadou Diallo (born September 2, 1975) was shot by four New York City Police Department plainclothes officers: Sean Carroll, Richard Murphy, Edward McMellon, and Kenneth Boss. Carroll would later claim to have mistaken him for a rape suspect from one year earlier.

The four officers, who were part of the now-defunct Street Crime Unit, were charged with second-degree murder and acquitted at trial in Albany, New York. A firestorm of controversy erupted after the event, as the circumstances of the shooting prompted outrage both inside and outside of New York City. Issues such as police brutality, racial profiling, and contagious shooting were central to the ensuing controversy.