A South Korean newspaper reports that a North Korean spy entered the South in 2003 by pretending to be an asylum-seeker.
South Korea's JoongAng Ilbo reports the North Korean joined a group of refugees who entered the South Korean Embassy in Beijing in 2002. The newspaper says he spent more than a year in South Korea, collecting information on Seoul's handling of refugees.
Officials in Seoul say the man returned to North Korea in April, then came back to the South a month later, where he surrendered to authorities.
South Korea's Yonhap news agency quotes government officials as saying they are investigating the 28-year-old on suspicion of spying for North Korea, but they doubt he actually conveyed any sensitive information.
Some information for this report provided by AP and Reuters.