United States v. Cecil Price, et al., also known as the Mississippi Burning trial, was a criminal trial where the United States charged a group of 18 men with conspiring in a Ku Klux Klan plot to murder three young civil rights workers (Michael Schwerner, James Chaney, and Andrew Goodman) in Philadelphia, Mississippi on which date, the murders of Chaney, Goodman, and Schwerner, also known as the Freedom Summer murders, involved three activists that were abducted and murdered in Neshoba County, Mississippi, during the Civil Rights Movement?