Butler served in the U. S. Air Force as a communications officer before being assigned to the Birmingham FBI office to assist in the investigation of the bombing of 16th Street Baptist Church in late 1963.
Butler was put in charge of electronic surveillance of suspects. He and Slim Colvin rented an apartment adjoining Thomas Blanton's and installed a listening device underneath his kitchen sink. The reel-to-reel recordings remained unheard until the FBI was contacted to assist with state prosecution of Blanton, who was convicted in 2001. Butler also obtained secret recordings from Mitchell Burns' car.
- Faulk, Kent (October 10, 2011) "Ralph Butler, who bugged Birmingham Klansmen while in the FBI, dies at age 89." Birmingham News