The Seoul Central District Court found the defendants not guilty, saying the agent, identified only by her surname Kim, was not held in captivity as she could have left the house if she wanted. The court also said they did not have the intention to detain Kim.

"The defendants asked Kim to come out and submit her computer or to open the door and let them check the computer," the court said. It added such action cannot be deemed as confining somebody, setting aside the question of whether that violates other laws.

She seems to have voluntarily decided not to leave out of concern secrets related to her duty could leak if she went out, the court added.

"I have been frustrated during the course of the trial, witnessing prosecutors and experts serving the power," Lee told reporters after the ruling was delivered. "I appreciate the people for keeping their eyes on this case until the ruling was made."

Prosecution immediately resisted the ruling, saying it is hard to accept the decision based on legal principles.

"We will thoroughly review the written judgment and decide whether to appeal the ruling," said a senior prosecutor, asking not to be named. (Yonhap)