John Joungwoong "Joung" Yai, 59, faced an initial court appearance Wednesday afternoon on charges he failed to register as an official agent of the Pyongyang government, which could lead to a 20-year prison sentence for the former merchant and restaurant investor.
"This investigation is ongoing to determine whether Yai's actions posed any threat to the national security of the United States," the FBI said in a statement issued Wednesday.
Yai was arrested without incident late Tuesday when FBI agents executed a search warrant at his Santa Monica apartment. The raid came amid growing tensions between the United States and North Korea over Pyongyang's nuclear weapons program.
An 80-page affidavit filed in support of the warrant alleged that Yai was an agent of the North Korean government between December 1997 and April 2000. United States law requires citizens acting as agents of foreign governments to formally register themselves with the federal government.
"He was tasked by North Korean officials to obtain classified information and to identify and recruit other agents to meet with North Korean officials abroad," the FBI said. "Yai maintained contact with his North Korean handlers through facsimiles, e-mail messages and personal overseas meetings. The communications sent between Yai and his North Korean contacts were written with word substitution codes to conceal the true content of the communications."
The nature of the information sought by Pyongyang was not revealed nor was it clear whether or not Yai was able to actually get his hands on sensitive materials or if he had successfully been able to recruit anyone else into his alleged conspiracy.
Los Angeles is home to one of the largest ethnic Korean communities in the United States. Yai was believed to have lived in the area for about 20 years, the Los Angeles Times said.
Yai's wife, 47-year-old Susan Youngja Yai, was charged in the investigation with making false statements to U.S. Customs agents in April 2000 when she and her husband returned to the United States from a trip to the Czech Republic and Austria where they met with allegedly North Korean officials. At the time, the FBI said, Customs agents found they were carrying more than $18,000 in cash that they had failed to declare.
A summons for Mrs. Yai was expected to be issued at a later date, the FBI said.
The arrest appeared to catch other members of Yai's family off guard. Yai's sister-in-law, Young Ro, told reporters Tuesday night that Yai "loved America" and didn't appear to have the English proficiency or computer skills needed to be a successful spy.
"I don't believe he would do that at all," she told the Times. "I don't think he's that smart."