The Missouri Supreme Court has set a date for the execution of a man sentenced to death for killing a southwest Missouri sheriff’s deputy in 1996.

Cecil Clayton (courtesy; Missouri Department of Corrections)

Cecil Clayton (courtesy; Missouri Department of Corrections)

The execution of 74-year-old Cecil Clayton is set to happen between 6 p.m. March 17 and 5:59 p.m. March 18, at the state prison in Bonne Terre.

Clayton shot Barry County Deputy Christopher Lee Castetter in the head. Castetter had responded to a call about a suspicious vehicle parked outside the home of the mother of Clayton’s ex-girlfriend. He died a short time later.

Clayton’s ex-girlfriend had broken up with him earlier that night and prosecutors said that prompted him to take a loaded gun to the mother’s home. They said Clayton had not expected Deputy Castetter to show up at the home.

Clayton’s attorneys have argued that he should not be executed because he is not competent to understand his punishment due to a deteriorating mental state, in part because of a head injury suffered at a sawmill 25-years prior to the murder. A neuro-psychologist has testified that Clayton lost about 8-percent of his brain in that accident.

The time Clayton’s execution has been set for is unusual. The state has scheduled executions to happen at 12:01 on the morning of the given date since the late 1930s.  A spokesperson for the Court said it is accommodating a request from the Department of Corrections.

The state is scheduled to on Wednesday carry out the execution of Walter Storey for the 1990 murder of a neighbor, Jill Frey.