William Clifford (Billy) Breen; Undercover FBI Operative

William Clifford (Billy) Breen, 66, the longtime undercover FBI operative who helped solve the 1979 assassination of U.S. District Judge John Wood. Breen outlined his career in his biography released this year, “The Insider: The FBI’s Undercover ‘Wiseguy’ Goes Public.” During his career as a police officer, con man and then undercover operative, Breen helped implicate mobsters, drug dealers, bookmakers and major organized crime figures in 39 states. He infiltrated the drug and gambling ring operated by Jimmy Chagra of El Paso, providing crucial information that led to the convictions of Chagra and four others in Wood’s death. Wood was shot to death outside his San Antonio home on May 29, 1979, the day that Chagra was to stand trial on drug charges. In Plano, Tex., on Friday of a brain tumor.