SEOUL - The South Korean military refused Thursday to release the suicide note of a soldier who killed five comrades, as speculation mounted that his shooting spree was triggered by bullying on his barracks.
The 22-year-old sergeant, surnamed Lim, was captured alive Monday after a 24-hour standoff with thousands of troops ended when he shot himself in the chest.
Two days before he had opened fire on members of his own unit at a guard post near the tense border with North Korea, killing five and wounding seven.
Before his unsuccessful suicide attempt, the cornered Lim wrote a note which the defence ministry said it was withholding at the request of the families of the soldiers who were killed.
"They said it would be good to disclose it fully after our investigation verifies all the related facts," ministry spokesman Kim Min-Seok told reporters.
Kim has already indicated that Lim expressed regret for his actions, but media reports say the note also detailed how bullying drove him to despair.
Bullying in the armed forces is a sensitive issue in South Korea, where the vast majority of personnel are those serving their mandatory two-year military service.
Mistreatment of fresh conscripts used to be rampant and was blamed for a number of suicides and similar shooting sprees in the past.
Measures have been taken to stamp out the practice, but experts say those who struggle to adapt to military life are often isolated and humiliated.
Media reports have suggested the families of Lim's victims want the note withheld because its contents might reflect badly on their sons.
Several newspapers cited unspecified sources as saying Lim had detailed the bullying he suffered, with the JoongAng Ilbo saying he compared himself to a squashed insect.
The Dong-A Ilbo said Lim wrote it would have been "difficult for anyone if they were in my situation".
Defence minister Kim Kwan-Jin had annoyed the victims' families by hinting Wednesday that bullying had been a factor.
"It is one of several issues we are paying attention to," he said in a meeting with lawmakers.
Lim joined the army in 2012 as was only three months away from being discharged.
He had difficulty adapting to the military, and psychological evaluations had advised senior officials to pay special attention to him.