A man murders three innocent teens in 1966, is sentenced to death and later is released from prison to kill again. This is the case of Kenneth Allen McDuff aka "The Broomstick Killer".
Resources:
Articles: "Free to Kill" by Gary Carthwright, Texas Monthly, August 1992. "McDuff Likely to Take Grisly Secrets to Grave" by Mike Cochran for the Associated Press, published in the Lubbock-Avalanche Journal, 1996.