There have been multiple references to the period on r/100yearsago
The Red Summer of 1919 was a period leading into the great depression where returning unemployed veterans were facing joblessness, both African American and White. The United States was leaving a wartime economy, with the reduction of wartime industry jobs were becoming scarcer in American cities. African American veterans of the First World War had returned after serving their country and felt that they had earned equal rights with their service. Industry had started to use African Americans and immigrants as strikebusters in cities. The National Association for the Advancement of Colored People(NAACP) had been formed just a decade prior, and its leaders were the target of J. Edgar Hoover's investigative bureau to confirm the belief that were being influenced by outside national influences such as the Bolsheviks. Their agents were forced to conclude that there were no outside influences upon leaders such as W. E. B. Du Bois, as well as in any of the African Americans arrested during the Washington Riot. The social trends of the time were unemployment due to an economic downturn and a flood of new labor, African American pushback against oppression and intentional agitation by organizations such as newspapers, government agencies like Hoover's bureau and political boss cronyism.
I'm going to focus attention on the Omaha riot on September 28 through the morning of the 29th, 1919. Will Brown was arrested in connection to a report of a sexual assault on a white woman, and a mob of approximately five thousand formed to bring him out of the brand new courthouse that night. The crowd nearly lynched its mayor, Ed Smith, after he came out of the courthouse to try and talk the crowd down. We'll come back to Ed Smith. Will Brown was eventually brought out by the mob and lynched very publicly.
A month prior to this event, 500 African Americans came down from Chicago and its outlying areas to very publicly break a strke on Omaha's meatpacking industry. The local newspaper had been reporting on inflation on food prices that had struck across the nation but was at its worst in Omaha as proved by the United States Labor Bureau. There were allegations during this time of African Americans assaulting white women and the newspaper regularly reported on these rumors with inflammatory statements like “our women must be protected at all costs.”
Ed Smith was rather recently elected part of a city reform movement attempting to take back the city from the entrenched political machine of Tom Dennison. Tom Dennison was in an alliance with the Omaha Daily Bee, the newspaper publishing inflammatory statements like the above. The president of the local Chapter of the NAACP, Rev. John A. Williams accused the Bee of being a mouthpiece of Tom Dennison and stirring up violent sentiment.
Ellis, Mark. “J. Edgar Hoover and the ‘Red Summer’ of 1919.” Journal of American Studies 28, no. 1 (n.d.): 39–59.
Menard, Orville D. “Lest We Forget: The Lynching of Will Brown, Omaha’s 1919 Race Riot,” Nebraska History 91 (2010): 152-165.
Menard, Orville D, and Laurie Smith Camp. River City Empire: Tom Dennison’s Omaha. Lincoln: Bison Books, 2013.