On July 4, soldiers on guard duty found the unidentified person near the ammunition depot inside the Navy's Second Fleet Command in Pyeongtaek, 70 kilometers south of Seoul. When asked for a countersign, the person failed to give an answer and ran away, according to the Navy.
An immediate manhunt was launched but failed to catch or identify the person, officials said.
Officials said they have found no signs of outside infiltration based on its analysis of CCTV footage, fences around the compound and witness accounts. Authorities have been focusing the investigation on members of the fleet.
During the investigation, one of the soldiers stationed at the base confessed that the unidentified person was him. But that confession turned out to be false, officials said.
"Over the course of the probe, a petty officer second class confessed to the alleged suspicious acts, but he later told investigators that he did so falsely as he was coerced by a senior officer," a Navy officer told reporters.
The lieutenant commander allegedly told soldiers under his command that one of them should make a confession so that the case would not trouble the entire unit, he added.
Taking the case seriously, Defense Minister Jeong Kyeong-doo sent eight investigators to the command earlier in the day and called for a thorough probe, according to a defense ministry official. (Yonhap)