SEOUL, June 20 (Xinhuanet) -- The South Korean soldier who killed his eight colleagues in a shooting spree is believed to have plotted the incident after he was scolded by comrades, South Korean Yonhap News Agency quoted military investigators as saying on Monday.

    The soldier, 22-year-old Pfc. Kim Dong-min, threw a hand grenade and fired 44 rounds from K-I rifles into a front-line army barracks, killing eight colleagues and injuring two others in early hours of last Sunday.

    Kim was arrested shortly after the shooting incident, and is now under investigation by army investigators.

    "I believe he premeditated the incident, though I can't precisely say he plotted it. We found Pfc. Kim told his colleague that he would crush their platoon one day," Brig. Gen. Park Cheol-su, the chief army investigator, was quoted by Yonhap as saying ina press conference.

    "During a questioning, he also said he initially attempted to kill all platoon members," said Park. Kim's platoon had 25 members.

    Kim went on the shooting spree out of anger over his seniors, who bullied and verbally molested him several times, Park told reporters.

    "Kim is a timid person who is easily hurt by trivial words," Park said, adding that he didn't suffer any type of physical abuse.

    Sunday's incident took place at an army guard post inside the 4-kilometer-wide demilitarized zone (DMZ) that bisecting South Korea and the Democratic People's Republic of Korea (DPRK).

    South Korea carries out mandatory military system which requires healthy male citizen over 20 years old to serve in the military for 24-28 months.

    The South Korean troops were often revealed to have human rights abuses of rank-and-file soldiers by local media. Enditem