A fourth Marine accused of participating in the December beating of a fellow trainee has pleaded guilty to charges that will keep him in prison for nine months.

Pvt. John Clough, 18, pleaded guilty Monday to conspiracy, making provoking gestures, assault consummated by battery, solicitation and violating the Marine Corps ban on hazing.Clough also received a bad-conduct discharge and was commanded to forfeit all pay and allowances. He was sentenced at Parris Island, S.C.