On September 15, 1963, members of the Klu Klux Klan bombed a predominantly African-American church in Birmingham, Alabama during the Civil Rights Movement. The blast at the 16th Street Baptist Church killed four young girls and injured twenty other people. Despite an investigation by the FBI, no one was charged with responsibility for the crime until Robert Chambliss was convicted of murder in 1977. His accomplices, Thomas Blaton, Jr. and Bobby Frank Cherry, were not tried and convicted until about twenty-five years later.
Learn more about the 16th Street Baptist Church bombing and the trials of Blanton and Cherry from NPR.