Seoul: South Korea`s military says a marine who killed four colleagues at a front-line base showed signs of mental trouble long before the rampage took place.
Chief investigator Kwon Yeong-Jae told reporters on Tuesday that the 19-year-old corporal had a "psychological problem”. He didn`t elaborate.
The corporal killed four marines and wounded another in Monday`s shooting attack on Ganghwa Island just south of the tense maritime border with North Korea.
Kwon says investigators found a note in which Kim lamented the state of his life. The marine tried unsuccessfully to kill himself by detonating a grenade following the shooting.
Kwon says marine officials had been trying to monitor Kim before the shooting.