https://www.npr.org/2022/01/03/ [login to see] /seoul-north-korea-defector-likely-made-rare-border-crossing-back
A person who crossed the border from South Korea into North Korea on New Year's Day was likely a defector who had slipped through the same heavily fortified frontier in the other direction to settle in South Korea in late 2020, the military said Monday.
South Korean surveillance equipment detected an unidentified person moving into North Korean territory across the eastern portion of the border on Saturday. The military said a security camera showed a person earlier Saturday crawling over a barbed-wire fence along the southern edge of the border.
On Monday, the Defense Ministry said in a statement it suspects an earlier North Korean defector was the border crosser and that it is trying to confirm related information.
A ministry official said the statement refers to a former North Korean citizen who was captured south of the border in November 2020. The man identified himself as a former gymnast and told investigators that he had crawled over barbed wire fences to defect before being found by South Korean troops, the official said, requesting anonymity citing department rules.