Ex-PLA signals officer timed his eavesdropping on Korean and US military bases to allied drills

A retired Chinese army signals officer accused of intercepting military communications around South Korean and US bases timed most of his operations to coincide with allied military exercises, according to his indictment, which a South Korean opposition lawmaker obtained from the Justice Ministry on 20 October.

The document, released by People Power Party lawmaker Kim Meen-geon, says the man carried out 13 surveillance sessions between March 2024 and August 2026, and that seven of them overlapped with combined South Korea-US drills or trilateral drills that also involved Japan, the JoongAng Ilbo reported. The suspect had served for about four decades in an intercept unit of the People's Liberation Army's general staff before retiring with a rank equal to lieutenant colonel.

His first session, according to the indictment, ran from 12 to 14 March 2024 at a hotel near Kunsan Air Base, home to the South Korean air force's 38th Fighter Group and the US 8th Fighter Wing, while the allies were holding their Freedom Shield exercise. On 29 June that year he was at a hotel near the Busan naval base, on the last day of the first Freedom Edge drill, which brought together the US carrier Theodore Roosevelt, a South Korean Aegis destroyer and a Japanese helicopter carrier.

The pattern continued. He set up near Camp Humphreys, the seat of the Combined Forces Command and the US Eighth Army, during Ulchi Freedom Shield in August 2025 and during Freedom Shield in March 2025. He returned to Kunsan during the Freedom Flag air exercise in late 2025 and during Freedom Shield in March 2026, and went to Gwangju Air Base during Freedom Flag in April 2026. Kunsan, the US air base in Korea closest to China and Taiwan, was his most frequent target, with seven of the 13 sessions.

Prosecutors in Pyeongtaek charged him on 1 September together with a second former PLA member, Yonhap reported when the indictment became public on 29 September. They say he used receivers and antennas set up in hotel rooms to capture traffic between military aircraft and control towers, gathered 13.9 terabytes of recordings and carried them to China. The second man, a 45-year-old former PLA special forces member who ran a military supply shop outside Camp Humphreys, is accused of recruiting a civilian employee and soldiers at the base and passing on joint exercise material and command personnel details on 12 occasions.

At his first hearing on 13 October, the 65-year-old suspect, a Chinese national surnamed Ma, admitted the charges through an interpreter, the Digital Times reported. The court decided that much of the evidence touches on military secrets and will be examined behind closed doors. Police have said they are still investigating who received the recordings.

Prosecutors argue that listening in this way lets an outsider infer classified details such as flight operations and aerial reconnaissance plans. He was charged with benefiting the enemy rather than espionage, because a revised Criminal Act that extends espionage to spying for foreign states other than North Korea only took effect on 13 September, after the indictment.

The disclosure lands as Washington presses Seoul on counterintelligence. According to the JoongAng Ilbo, a senior US official warned on 9 October that South Korea must meet the alliance's long-standing intelligence and counterintelligence standards, and the United States has begun limiting some of the intelligence on North Korea it shares with the South. South Korean analysts quoted by the paper said Seoul needs firmer rules on Chinese military espionage, and warned that fragments of exercise data can reveal sensitive operational patterns once they are pieced together.