A North Korean defector who returned to the communist country in May had probably been threatened by the North before going back, Seoul's Unification Ministry said Tuesday, referring to a woman whom the North used to propagandize against the South.

"We suspect Park went to the North in fear for her family members' safety in North Korea," a Unification Ministry official said, referring to Park In-suk, a North Korean who returned to the communist country after spending six years in Seoul following her defection in 2006.

"An investigation conducted by a related organization found the North somehow threatened Park about the safety of her family members in the North," he said.

Last month, North Korea's official media reported the defector's return, describing her life in Seoul as miserable and exploited. The report quoted Park, whom the North identified by the first name of Jung-suk, as saying she was lured to the South by South Korean intelligence officials.

Refuting those claims from the North, the ministry official called on the communist country to stop threatening its defectors here.

Another female defector residing in South Korea said, "Park had been agonizing after getting threatening calls from the North in April."

The official said the government is planning to take measures to better protect about 23,000 North Korean defectors residing here from similar threats. (Yonhap)