The western front of the Demilitarized Zone and the now-shuttered Kaesong industrial park are seen from a border area in Paju, Gyeonggi Province, in this photo taken in May. (Yonhap) A North Korean soldier is under investigation after crossing the Military Demarcation Line into South Korea on Tuesday night, Seoul’s military said Wednesday.The Joint Chiefs of Staff said it secured custody of the North Korean soldier along the central section of the inter-Korean border on Tuesday night.“Relevant details are under investigation by related authorities,” the JCS said in a statement.The soldier is believed to have expressed a wish to defect to South Korea, according to military sources.The MDL is the de facto inter-Korean border established under the 1953 Armistice Agreement, which halted hostilities in the 1950-53 Korean War. The line runs through the Demilitarized Zone roughly 50 kilometers from Seoul and about 150 kilometers from Pyongyang.This marks the fourth known case of a North Korean crossing into South Korea since the Lee Jae Myung administration began in June 2025, as well as the second involving a North Korean military service member.In October last year, another North Korean soldier crossed the MDL along the central section of the border and expressed a wish to defect. The South Korean military secured custody of the soldier and handed the person over to relevant authorities.Civilian crossings have also continued. On July 3 last year, a North Korean man crossed the MDL along the central-western section of the border. On July 31, another North Korean man was rescued by the South Korean military south of the median line in neutral waters of the Han River estuary.Military and intelligence authorities are believed to be looking into the latest soldier’s unit, rank and motive for crossing the border.