Keith William Zettlemoyer was born on June 4, 1955, in Aberdeen, Maryland, as the eldest of five children. He held various jobs, including photographer, custodian, and maintenance worker. In May 1980, Zettlemoyer and an accomplice, Kenneth Kipple, committed a robbery at a RadioShack near Sunbury, Pennsylvania, binding a security guard and stealing electronic equipment. Kipple was later apprehended and implicated Zettlemoyer in the crime. Zettlemoyer confided in his friend, Charles DeVetsco, about the robbery. DeVetsco reported this to authorities and was scheduled to testify against Zettlemoyer. Fearing the testimony, Zettlemoyer decided to eliminate DeVetsco.

In the early hours of October 13, 1980, Zettlemoyer kidnapped Charles DeVetsco near Selinsgrove, Pennsylvania, and transported him to a secluded area in Harrisburg. There, he shot DeVetsco twice with a .22 caliber weapon while he was handcuffed in a van. Zettlemoyer then dragged DeVetsco into nearby woods and fatally shot him twice in the back with a .357 Magnum revolver. Police officers, hearing gunshots, arrived at the scene and apprehended Zettlemoyer, who claimed he was shooting rats. They discovered DeVetsco's body shortly thereafter.

Zettlemoyer was convicted of first-degree murder on April 24, 1981, and sentenced to death. After 14 years on death row, he waived his appeals, citing mental anguish due to a "brain disease." Despite arguments from his former lawyers and DeVetsco's mother about his mental competence, courts upheld the execution. On May 2, 1995, Zettlemoyer was executed by lethal injection at the State Correctional Institution – Rockview, becoming the first person executed in Pennsylvania since 1962.