A U.S. Air Force F-35A takes off from Osan Air Base during a South Korea-U.S. joint air drill in February. / Republic of Korea Air Force

Two Chinese nationals who had previously been released after being caught filming near a South Korean military base were detained again two days later for taking similar photographs at the same site, police said.

According to the Gyeonggi Nambu Provincial Police Agency, U.S. military personnel reported around 11 a.m. on Apr. 23 that two Chinese citizens, including a man identified as A, were photographing fighter jets near Osan Air Base in Pyeongtaek, which houses U.S. forces. Responding officers arrested the individuals on suspicion of violating S. Korea’s Protection of Military Bases and Installations Act.

Authorities later confirmed that the two had been involved in a similar incident just two days earlier, on Apr. 21, when they were found taking unauthorized photos near the same base. At that time, the police conducted a joint investigation with the National Intelligence Service and the Defense Counterintelligence Command.

After determining there were “no indications of espionage,” the investigation was closed and the men were released after about eight hours without charges.

Despite having been warned and released without charges just days earlier, the same individuals returned to the site and repeated the same behavior—raising renewed concerns about the effectiveness of the initial response.

Yet again, authorities reviewed the photographs and, finding no apparent signs of espionage or national security threats, opted to release the pair without further action.

The investigation found that the men had used high-end camera equipment to photograph aircraft flying overhead from public streets around the base. Under current law, taking photos of aircraft in flight from non-restricted areas does not constitute a legal violation.

A similar case occurred last month, involving two Chinese teenagers who were booked on suspicion of violating the same law.

On Mar. 21, the teens allegedly used DSLR cameras and smartphones to photograph fighter jets during takeoff and landing near the 10th Fighter Wing base in Suwon.

Further investigation revealed that the pair had taken thousands of photos not only near that base but also at other key sites, including Osan Air Base, Camp Humphreys in Pyeongtaek, and the Air Force base in Cheongju. In addition, they had captured images at several major international airports—Incheon, Gimpo, and Jeju.

Police said they are continuing to investigate the case, and noted that one of the teenagers told authorities his father is a member of China’s public security bureau.