San Diego ? A 22-year-old Marine lance corporal was sentenced Saturday to eight years in the brig and a possible dishonorable discharge in connection with the killing of an unarmed Iraqi man last year, the toughest sentence yet meted out in the high-profile case.

Lance Cpl. Robert Pennington pleaded guilty to kidnapping and conspiracy in the shooting death of Hashim Ibrahim Awad, 52, in the village of Hamandiya. In exchange for his plea, a murder charge was dropped.

In previous hearings at Camp Pendleton on the case, a Navy corpsman was sentenced to 12 months in the brig, a private first-class to 18 months, and two lance corporals to 21 months each.