The murder of Addie Mae Collins, Denise McNair, Carole Robertson and Cynthia Wesley

The bombers were known early and convicted late. Cherry was a suspect within days of the explosion, and by May 1965 the Bureau had formally named four members of a Birmingham-area Klan group, Robert Chambliss, Thomas Blanton Jr., Bobby Frank Cherry and Herman Frank Cash. No timing-device fragments were found in the wreckage, and FBI experts never established how the bomb was triggered. Director J. Edgar Hoover blocked prosecution, and in 1968 the file was closed. The first break came from a state prosecutor. Bill Baxley, Alabama's attorney general in the 1970s, wanted to try the four men but was not receiving the FBI's evidence; after Hoover's death in 1972, and by going over the Bureau's head to the Justice Department with the press in tow, he obtained limited access to its material. An investigator identified Chambliss's niece, whose information helped convict him, and in 1977 a jury found Chambliss guilty of the murder of Denise McNair. Baxley later said he could have convicted Blanton at the same time had the FBI given him its recordings; the Birmingham office said it had not known they existed. The second break came two decades on. In 1993 FBI officials met Birmingham's Black ministers, and the Bureau reopened the case, assigning Special Agent William Fleming and Ben Herren, a Birmingham police sergeant later hired by the FBI. More than 130 witnesses had died. Fleming searched the office's own storage and found a box with a note reading bomb; inside were the 1960s surveillance tapes, from a microphone hidden in Blanton's kitchen in 1964 and a recorder an informant carried in his car in 1965. On the kitchen tape Blanton told his wife about the meeting where, in his words, they planned the bomb; on the car tape he said the FBI would not catch him when he bombed his next church. The agents re-interviewed people who had been silent for decades, and in 1997 went to Texas to see Cherry. His former wife, a granddaughter, a former co-worker and a brother-in-law all said he had claimed to place the bomb under the church stairs and light the fuse. Blanton and Cherry were indicted in 2000. Blanton's jury heard the tapes and convicted him in about two and a half hours in May 2001; Cherry, tried after a year's delay over his competence, was convicted in less than a day in May 2002. The solve was not forensic. It was the Bureau's own forgotten recordings, and witnesses who were finally asked.