A North Korean defector who has been working as a Seoul city official assisting fellow refugees is under investigation on charges of spying for the communist country, officials said.

The 33-year-old identified by his surname Yoo is suspected of handing information about defectors to the North’s intelligence agents.

He was apprehended by the National Intelligence Service on Jan. 11.

The contract public servant Yoo was hired by the Seoul Metropolitan Government through an employment procedure for North Korean defectors on June 9, 2011, and worked at the welfare policy bureau.

“He was quiet and did not talk much. His job was support in payroll administration for public servants. He was not in charge of important tasks,” said a former director of the bureau in 2011, who is now working in a different department.

“There was nothing very special or suspicious about him, but he was very clumsy at work,” the former director said.

Yoo’s other tasks were to receive phone calls and sometimes to have consultations for North Korean defectors.

However, it is said that information could have been leaked about North Korean defectors residing in Seoul.

“The city government is keeping a close eye on the case, waiting until the result of the investigation comes out,” said Lee Chang-hak, the spokesperson for the Seoul Metropolitan Government, emphasizing he had limited access to information, such as names and phone numbers of public officers that were withheld by the city government.

Yoo, 33, had fled alone from North Korea in 2004.

He graduated Chongjin Medical University in North Hamgyeong Province and worked as a surgeon for a year.

He told media after his defection to the South that he had come to realize the reclusiveness of the North’s authoritarian regime while he was working in China to smuggle goods.

He studied Chinese and management at a Korean university and worked at a trading company with his fluent English and Chinese skills.

His family is said to be still in North Korea.

It is the first time a North Korea defector working at a public office has been arrested for espionage.

Last year, Kim Young-soo was jailed for four years for spy activities. He had been ordered to watch a human rights activist for the North and kill Kim Jong-nam, the eldest son of late North Korean leader Kim Jong-il, when he was in China.

Other recent North Korean spy cases include Won Jeong-hwa, 38, who was jailed for five years for leaking classified information on the locations of key military installations, lists of North Korean defectors and personal information on South Korean military officers to the North; and Kim Mi-hwa, 38, who was arrested in 2010 for obtaining information on Seoul’s metro system from a high-ranking official at Seoul Metro, the operator of subway lines No. 1 to 4, and sending them to the North.

Safety concerns about North Korean defectors in Seoul rise about the possibility of a leak of their information.

Lee Han-young, a nephew of a former wife of late former North Korean leader Kim Jong-il, was shot to death in 1997 in Bundang, Gyeonggi Province, allegedly by North Korean spies.

Several attempts to assassinate high-profile defectors such as Hwang Jang-yop, a former top North Korean official who died in 2010, occurred in the past.

By Kim Young-won (wone0102@heraldcorp.com)