FORT STEWART - Attorneys for an Army Reserve soldier on trial for murder at Fort Stewart say he killed a superior because he was dehydrated and delirious from a crash diet after being ordered to lose weight.

Staff Sgt. Rashad Valmont faces life in prison if a court-martial convicts him of premeditated murder in the slaying of Master Sgt. Pedro Mercado at Fort Gillem near Atlanta.

Valmont admits shooting Mercado six times after he refused the soldier's vacation request last summer. Valmont drove to a police state and turned himself in.

Valmont's attorneys say two days before the killing he was ordered to lose 3 percent of his body fat within a single day.

A military psychiatrist testified Wednesday she believes the soldier was delirious from dehydration and other effects of fasting.