I think I've seen this movie
Mann is a mysterious World War I veteran who is scouting out land to buy. He comes to the town of Rosewood, a small predominantly black town in Florida. Rosewood is home to the Carriers, an upwardly mobile black family, helmed by Aunt Sarah and her proud, headstrong son, Sylvester. Mann soon meets Beulah "Scrappie" Carrier, Sylvester's younger sister and the two quickly fall in love.
Aunt Sarah works as a housekeeper for James Taylor and his wife, Fanny, a white couple who live in the neighboring town of Sumter. Fanny, who has a history of cuckolding her husband, has a rendezvous with her lover while her husband is at work. Fanny argues with her lover, who ends up beating her. Aunt Sarah and her granddaughter, Lee Ruth, overhear the argument and subsequent beating but do not intervene. A distraught Fanny, despairing of explaining her injuries to her husband, leaves her house and calls for help. She then tells several townspeople that she has been attacked by a black man. The white residents readily believe Fanny's claim. Hearing of an escaped black convict, a posse from Sumner and nearby towns go to Rosewood to investigate. The black residents of Rosewood quickly become targeted by a white mob, including men from out of state and members of the Ku Klux Klan.
As a stranger, Mann is afraid of being accused and subsequently lynched. He plans to leave town over the protests of several Rosewood residents who have met in church to discuss plans to defend their community. Outside the church, Mann clashes with John Wright, the owner of a general store, one of the few white residents of Rosewood. Wright is also engaging in a torrid extramarital affair with Jewel, a black woman. Mann then leaves.
When the posse arrives at the Carrier home, Aunt Sarah attempts to placate the angry crowd. However, when she announces that Fanny Taylor's attacker had been a white man, someone in the crowd shoots her. She subsequently dies of her injuries. The posse comes and Sylvester shoots and kills them. After Aunt Sarah's murder, the posse launches an outright assault on Rosewood. Mann is on his way out of town when he witnesses the lynching of Sam Carter, the blacksmith. Changing his mind about leaving, Mann returns to Rosewood to fight alongside the residents. Some white men who live in Rosewood help black Rosewood residents escape. Railroad conductors smuggled people out of town on trains. Wright asks the train conductors to pick up the women and children while his wife hides several other African-Americans in their home. Other whites attempt to squelch the rising violence with little success.
The posse swells in number. Believing that James Carrier held information about the escaped convict, they seek him out. After making an unsuccessful attempt to intervene on James' behalf, Wright reluctantly allows Sheriff Walker take Carrier into custody because the officer said he only wanted to question him. When Carrier says he doesn't have any information, he is immediately shot by one of the mob. Wright gets upset and the mob accuses him of being soft on blacks.
The violence escalates and spills out into neighboring towns. But when the posse get to the border of Alachua County, a group of armed white men block the roads and turn them back. Surviving members of the Carrier family eventually escape. Scrappie and Mann finally share a kiss before Mann departs with Sylvester. The two plan to meet up later. After the violence eventually dies down, James confronts Fanny, telling her that "they haven't caught your ****** yet." Realizing that Fanny has lied to him about the true cause of her injuries and had affairs with other men, James beats her. Officially the death toll was eight people total, two whites and six blacks. Other accounts by survivors and several African-American newspapers were of a higher toll.