Oklahoma ? A 74-year-old man was executed Thursday for nearly decapitating his stepson with a knife more than two decades ago.

John A. Boltz was the oldest death row inmate executed in Oklahoma and the third-oldest in the country since capital punishment was reinstated in 1977.

Officials had trouble finding a vein to inject the lethal drugs, delaying the execution for more than an hour at the Oklahoma State Penitentiary. Boltz was pronounced dead at 7:22 p.m.

Boltz was 52 when a jury convicted him of the 1984 killing. Doug Kirby, 22, had driven to Boltz’s home to discuss threats Boltz had made against his estranged wife, who had asked for a divorce, authorities said.

The medical examiner said Kirby was stabbed eight times in the chest and abdomen and suffered a cut in the neck that nearly decapitated him. Boltz claimed he acted in self-defense.