The sergeant who killed five soldiers in a shooting rampage last month had been taunted and ostracized while in high school and during his military service, the Army said Tuesday.

Announcing the results of the three-week investigation into the June 21 shooting, the Army said that the 22-year-old sergeant, surnamed Lim, was driven to go on the shooting spree after being mocked by his senior and junior colleagues.

A series of humiliating pictures that Lim’s fellows drew on the cover of the daily patrol logs particularly enraged him on the day of the shooting, investigators said. Weak, short and slightly bald, Lim was depicted as various silly-looking characters in the logs.

“We concluded that Lim’s crime was premeditated. … Our investigation found that (before the shooting) he reminisced about the stress he suffered due to being ignored and mocked by senior officials and fellow soldiers after joining the Army,” Brig. Gen. Sun Jong-chul, the head of the Army’s Military Police told a press conference.

“Our probe also suggested that (before the shooting) Lim thought he could not live well even after being discharged from the Army. He thus thought of killing all of his fellow soldiers and then killing himself.”

After completing his daily border defense duty last month, Lim detonated a hand grenade and fired at his colleagues in and around his barracks at a unit of the Army’s 22nd Division. The shooting left five soldiers dead and seven wounded.

The worst shooting incident since 2005 sent shockwaves across the nation, prompting calls to improve the outmoded, closed military culture and counseling program, particularly for those working at remote border units.

During the press conference, the Army also revealed the content of the note Lim wrote before he attempted suicide. Lim was arrested right after he fired at his upper body between the chest and left shoulder some 43 hours after he ran away.

“In my situation, anybody might have felt that it was much more painful to live than to die. I am to blame for much, but they are also to blame for some,” the note reads. “Children may harass dogs, may kill insects or worms without any guilty feelings. But they don’t really understand how much pain their actions bring.”

As bullying was cited as the primary reason why Lim went on the shooting rampage, the families of the victims expressed outrage, saying that the victims were being treated as though they were to blame.

The military investigators have arrested Lim on charges of killing his military seniors.

In the wake of the shooting, the military dismissed the majority of senior leaders in the frontline division from their posts for failing to properly supervise their soldiers and other issues including dereliction of duty.

The military also sent 150 soldiers, rated as those requiring special observation, to rear-area units after conducting a full-scale survey of the troops to check if they were unfit for a border defense duty. Lim was once rated as unfit for a frontline mission.

By Song Sang-ho (sshluck@heraldcorp.com)