Byron de la Beckwith was tried for the same murder three times. In 1964, it just wasn't generally considered illegal for a white man to kill a black man in Mississippi.
Sources & Further Reading:
Massengill, Reed (2024). Portrait of a racist: Byron De La Beckwith and the Assassination of Medgar Evers. Univ. of Tennessee Press.
DeLaughter, Bobby (2001). Never Too Late: A Prosecutor’s Story of Justice in the Medgar Evers Case. Scribner.
Mitchell, Jerry (2020). Race Against Time: A Reporter Reopens the Unsolved Murder Cases of the Civil Rights Era. Simon & Schuster.
Evers, Myrlie (1967). For Us, The Living. Doubleday & Company.
Tyson, Timothy (2017). The Blood of Emmett Till. Simon & Schuster
Vollers, Maryanne (1995). Ghosts of Mississippi. Little Brown & Company.
Martin, Ralph (1983). A Hero For Our Time. Bandwagon, Inc.
Baden, Michael (2006). Exhumation. in Spitz & Fisher's Medicolegal Investigation of Death.

Rabid on the Subject of Segregation: Byron de la Beckwith, Pt 4
1:00:20

Black Monday: Byron de la Beckwith, Pt. 3
58:24

Sons of Mississippi: Byron de la Beckwith, Pt. 2
54:14