An appellate court in South Korea has upheld a three-year prison sentence for a former Marine commander convicted in connection with the death of a Marine during a flood rescue operation in 2023.

On Friday, the Seoul High Court affirmed the lower court's ruling against Lim Seong-geun, a retired two-star general who previously served as head of the 1st Marine Division. Lim was convicted of occupational negligence resulting in death, a charge under South Korean law that applies when a person responsible for safety in a professional capacity fails to exercise due care, resulting in fatal consequences.

The case stems from an incident in July 2023, when 20-year-old Corporal Chae Su-geun lost his life in a swollen stream during a military search mission in Yecheon, approximately 160 kilometers southeast of Seoul. The operation was launched in response to record-breaking downpours that caused widespread flooding across the region.

A special counsel team had requested a five-year prison sentence for Lim. South Korea's independent counsel system, invoked in cases of significant public interest where the常规 prosecution service may face conflicts of interest, allows for a prosecutor appointed independently of the regular justice apparatus to investigate and prosecute. The appellate court found that Lim's directives for aggressive search efforts at the time failed to adequately account for on-site conditions, leading to dangerous waterborne operations being conducted without proper safety guidelines or protective equipment.

The court also upheld sentences handed down by the lower court for additional defendants. Among them, Park Sang-hyun, former head of the 7th Marine Brigade who oversaw field operations at the scene, received an 18-month prison term.

Following the ruling, the mother of the late Corporal Chae spoke to reporters outside the Seoul Central District Court. The Korea Times reported that she addressed the press after the appellate court announced its decision.

Chae's death in 2023 triggered significant public outrage amid allegations that the administration of then-President Yoon Suk Yeol had attempted to interfere with or cover up a military investigation into the incident. The controversy surrounding the case contributed to broader political tensions during Yoon's presidency and became one of several flashpoints over military accountability and civilian oversight of the armed forces in South Korea, where all able-bodied men are subject to conscription and incidents involving service member deaths regularly draw intense national scrutiny.

The special counsel investigation into the matter was established to examine both the circumstances of Chae's death and the subsequent handling of the military's internal probe.