U.S. military officials have sentenced a soldier accused of killing Afghan civilians to three years in prison. The verdict was announced Friday at the court martial trial of Specialist Adam Winfield at the Joint Base Lewis-McChord in Washington state .

Winfield, who is 23, pleaded guilty to involuntary manslaughter and drug use. His rank was reduced to private and he was ordered discharged from the Army for bad conduct.

He is one of five members of an infantry unit, known as the Stryker Brigade, initially charged with the murder of three Afghan civilians prosecutors say was staged to look like combat casualties.

Winfield says he was pressured into taking part in the slayings.

Prosecutors say the man who was the alleged ringleader in the killings, Staff Sergeant Calvin Gibbs, remains in custody and faces a court martial later this year.