North Korea questioned last Friday a South Korean working at the Gaeseong Industrial Complex for leaking internal North Korean lecture materials.

The Unification Ministry said the North questioned the South Korean worker at its immigration office near the industrial complex for seven hours on Friday. South Korean government officials were in attendance at the time.

The questioning was focused on why the South Korean worker had sent a North Korean internal booklet to South Korea. But the worker was found to have committed the leakage by mistake.

According to the ministry, a North Korean worker had brought the booklet, which is used for lecturing North Korean employees, to a plant run by a South Korean company at the inter-Korean joint venture.

But the booklet was buried in merchandise produced by the factory and sent to South Korea. The South Korean company sent the booklet back to North Korea immediately after it found the material.