This explains a lot of why this North Korean soldier was in such a rush to defect across the DMZ:
A North Korean soldier who made a desperate dash across the border in November escaped after causing a person’s death, a South Korean newspaper reported Tuesday, quoting an unidentified intelligence official.
According to the report in newspaper Dong-A, the confession came from Oh Chung Sung—or Oh Chong Song, depending on the translation—over the course of a routine interrogation led by the the South Korean spy agency.
“I committed a crime in North Korea, which caused a death,” Oh reportedly said. Though South Korean media reported his comments about killing someone, the nature of the alleged crime was not clear.
The South Korean Ministry of Unification did not confirm the reports. “The investigation has not been completed yet,” a ministry spokesperson told reporters at a press conference, quoted in South Korean news agency Yonhap. “We cannot confirm specific details of the incident.” [Newsweek]
You can read the rest at the link, but it is not expected that the ROK will send the defector back to North Korea despite the murder.