A South Korean Marine who killed four colleagues in a shooting spree after complaining of bullying was sentenced to death on Friday after a court martial.
The 20-year-old corporal opened fire at a Marine Corps barracks on Ganghwa island near the North Korean border in July last year before trying to commit suicide with a grenade.
A Marine private found guilty of helping the corporal was sentenced to 20 years' imprisonment.
The corporal, identified only as Kim, and the private, surnamed Jung, told military investigators they had hatched their plan after being constantly bullied and beaten by superiors. Jung denied involvement in the actual shooting.
Military psychological tests conducted about a year before the shooting spree found Kim was mentally unstable and struggling to cope with service life. He had also been drinking before the rampage.
Kim can appeal the sentence. South Korea has not carried out executions since 1997, although the penalty remains on the statute books.
The elite Marine Corps is charged with guarding frontline islands in the Yellow Sea near the disputed border with the North.
The incident raised questions about standards of discipline and morale in the largely conscript 650,000-strong military.
In 2005 eight soldiers were killed and two seriously wounded when a soldier threw a grenade and sprayed bullets over sleeping colleagues at a frontline guard post north of Seoul.
The soldier in the 2005 incident alleged senior colleagues had bullied him.
In 2008 an army private struggling to adapt to military life threw a grenade at sleeping colleagues, wounding five.
And in June 2010, two Marines on another frontline island opened fire at a civilian passenger plane after mistaking the Airbus for a North Korean intruder. The aircraft was not hit.
Able-bodied South Korean men must undergo at least two years' military service, and some complain of abuse and harassment of junior soldiers by their seniors.
North and South Korea have remained technically at war since their 1950-1953 conflict ended only with an armistice instead of a full peace treaty.