SEOUL, May 13 (UPI) -- A South Korean reserve soldier killed two soldiers and injured three others at a reserve forces training ground Wednesday.
The shooter, a 23-year-old only identified by his surname Choe, opened fire on himself after his deadly rampage with a K-2 rifle, reported South Korean newspaper Donga Ilbo.
Speaking on the condition of anonymity, Choe's former supervisor said the reservist exhibited abnormal behavior during training but kept him enlisted as a "Class-B" soldier.
Yonhap reported the supervisor said Choe never laughed and was quiet -- and that the soldier never listened to his instructions or treated his fellow reservists with respect.
During his term of mandatory military service, Choe at one point followed his supervisor to his residence after a fight.
Neighbors and acquaintances of the shooter said Choe showed constant symptoms of mental illness. A 65-year-old local resident with the surname Kim said Cho used to walk about the area shirtless, shouting at the top of his voice.
"You could tell he was crazy," Kim told Yonhap.
Hours after the shooting the South Korean military released a two-page note found in Choe's military uniform.
The military spokesman said the note appeared to have been written on Tuesday, a day before the shooting.
According to the Donga Ilbo, the note read, "I want to die. To sleep forever. I want to kill everyone and I want to die too, that thought has become an obsession."
The note also mentioned instances of ongoing physical pain, and injuries from a burning incident.
An elderly neighbor of Choe said she noticed Choe turned strange after completing his mandatory military service, and said she didn't understand why Choe's family did not send him to hospital for treatment.
Of the three reservists injured on Wednesday, at least two were in a critical state and one was recovering from a coma.