Yu Seong-jin

The South Korean freed on Aug. 13 after 136 days of being held incommunicado in North Korea went on hunger strike at one point and was forced to sign a false confession that he was a spy, the government revealed Tuesday. Yu Seong-jin, an engineer with Hyundai Asan, was arrested in Kaesong on March 30 and released to coincide with a visit to Pyongyang by Hyundai Group chairwoman Hyun Jeong-eun.

The government said Yu had written several letters to a North Korean woman working at the joint Korean Kaesong Industrial Complex, whom he had met around 2005. In some of them, he criticized North Korea's political system, including the private life of leader Kim Jong-il and the situation of North Korean defectors.

"Another main reason for his detention was that Yu had talked to those around him about his close relationship with another North Korean woman whom he had met in Libya where he worked for Daewoo Construction in 1998," the government said. The woman was reportedly called back to North Korea later on suspicion of attempting to defect to South Korea.

Yu was summoned to the North Korean immigration office on March 30, where he was arrested. He was held at the Janamsan Inn in downtown Kaesong. Interrogations usually took between 30 minutes and two hours a day in the morning and afternoon. In some cases, they continued until midnight or 1 a.m. the following morning.

Investigators from Pyongyang reportedly wanted Yu to confess what he had said, what motives he had, and who was behind him, accusing him of "criticizing the supreme leader" and attempting to talk the woman into defecting. They also questioned him about the nature of his relationship with the woman in Libya between 1998 and 2000 and about whether he was involved in helping her to defect, the government said.

Yu denied his charges at first, but when the investigators presented evidence including the letters, he admitted them and wrote a confession. Investigators forced him to make a false confession that in Libya he had worked at the instructions of a South Korean intelligence agency. In protest, he even went on a hunger strike on April 23-25 but failed to stick it out and submitted a false written confession around May 17.

The investigators did not torture him in detention but interrogated him for long periods making him sit upright on a wooden chair. Investigators and security guards also shouted at and insulted him, forcing him a dozen times to get on his knees for three to five minutes. "They treated him inhumanely to the point of not turning off the lights when he had to sleep," the government added.