Kenneth Allen McDuff (March 21, 1946 – November 17, 1998) was an American serial killer. He was convicted in 1966 of murdering 16-year-old Edna Sullivan; her boyfriend, 17-year-old Robert Brand; and Robert's cousin, 15-year-old Mark Dunnam, who was visiting from California. They were all strangers whom McDuff abducted after noticing Sullivan; she was repeatedly raped before having her neck broken with a broomstick. McDuff was given three death sentences that were reduced to life imprisonment consequently to the 1972 U.S. Supreme Court ruling Furman v. Georgia. He was paroled in 1989.
McDuff was given a new death sentence and executed for a murder committed after his release, and is suspected to have been responsible for many other killings.
Kenneth Allen McDuff was born at 201 Linden Street in the central Texas town of Rosebud, the fifth of six children born to John and Addie McDuff. His father ran a successful concrete business during the Texas construction boom of the 1960s. McDuff was indulged by his family, particularly his mother Addie, nicknamed the 'pistol packing momma' because she threatened a school bus driver with a gun after the driver kicked off Kenneth's older brother Lonnie. Kenneth got the reputation of being a bully who was careful to pick only on the weak after the large but not strong McDuff lost a fight he had picked with an athletic and popular boy. As a result, he quit school and worked for his father's business doing manual labor. He would often brag in later interviews that the old ladies loved the way he mowed their lawns, making others jealous. McDuff was convicted of a series of burglaries and put in prison.
McDuff's criminal record began two years before his first murder conviction. In 1964, at age 18, McDuff was convicted of 12 counts of burglary and attempted burglary in three Texas counties: Bell, Milam, and Falls. He was sentenced to 12 four-year prison terms, to be served concurrently; however, he made parole in December 1965. McDuff briefly returned to prison after becoming involved in a fight but was soon released. While he had not been convicted of any murders at this time, his accomplice in the 1966 triple murder, Roy Dale Green, said that McDuff bragged openly about his criminal record and claimed to have raped and killed two young women.
On August 6, 1966, McDuff and Green, whom he had met around a month earlier through a mutual acquaintance, spent the day pouring concrete for McDuff's father. They then drove around, as McDuff said he was looking for a girl. At 10pm, Robert Brand (aged 17), his girlfriend Edna Louise Sullivan (aged 16), and Brand's 15-year-old cousin Mark Dunman were standing beside their parked car on a baseball field in Everman, Texas.
While cruising around, McDuff noticed Sullivan and parked around 150 yards away from the soon-to-be victims. He threatened the trio with his .38 Colt revolver and ordered them to get into the trunk of their car.
