On the afternoon of July 27, 1919, Eugene Williams, a black youth, drowned off the 29th Street beach. A stone throwing melee between blacks and whites on the beach prevented the boy from coming ashore safely. After clinging to a railroad tie for a lengthy period, he drowned when he no longer had the strength to hold on. This was the finding of the Cook County Coroner's Office after an inquest was held into the cause of death.
William Tuttle, Jr.'s book, Race Riot: Chicago in the Red Summer of 1919, includes a 1969 interview with an eyewitness. This witness was one of the boys swimming and playing with Eugene Williams in Lake Michigan between 26th Street and the 29th Street Beach. He recalled having rocks thrown at them by a single white male standing on a breakwater 75 feet from their raft. Eugene was struck in the forehead and as his friend attempted to aid him, Eugene panicked and drowned.
The man on the breakwater left, running toward the 29th Street Beach. By this time rioting had already erupted there precipitated by vocal and physical demonstrations against a group of blacks who wanted to use the beach in defiance of its tacit designation as a "white" beach. The rioting escalated when a white police officer refused to arrest the white man, by now identified as the perpetrator of the separate incident near 26th Street. Instead he arrested a black individual. Anger over this, coupled with rumors and innuendoes that spread in both camps regarding Eugene Williams death led to 5 days of rioting in Chicago that ultimately claimed the lives of 23 blacks and 15 whites, with 291 wounded and maimed.
The Coroner's Office spent 70 day sessions and 20 night sessions on inquest work and in examining 450 witnesses.
Link
Link for PBS site about Watts Riots
That does not consider race riots in Cincinnati on several occassions
over the last 150 years, it does not include Detroit, it does not include Washington, D.C., it does not include the notorious incident in Philadephia in which police dropped an improvised explosive device on a house they were beseiging, killing men, women and children inside, and burning down several square blocks of privately owned housing. It does not include many such incidents. Race is just one ugly cause of people having been shot down in the street, without regard for probable cause or due process. It's late at night here now, but if you like, i can continue tomorrow with the organized labor movement. Then there's the draft riots in New York in 1863. Given a little time and thought, i can come up with lots more of this.