Japanese police on Wednesday said its special unit that deals with alleged espionage arrested an ethnic Korean resident on suspicion of fraud -- as local media reported he was acting as a spy for North Korea. Japan is particularly sensitive to North Korean espionage activities in the country as operatives from and with links to the country have been blamed for abductions of Japanese citizens who were taken there to serve as language teachers for its spies. Japan also has a large population of residents with Korean nationality, the descendants of people from the Korean peninsula who either immigrated to Japan or were brought as forced labourers when Tokyo controlled the region as a colony from 1910-1945. The 49-year-old man was arrested Tuesday by the Tokyo Metropolitan Police public safety department -- which deals with crimes linked to spies and violent political and religious groups -- spokesman Kazufumi Suzuki told AFP. Suzuki offered a phonetic rendering of the man's name but had no romanised spelling, which was reported as Pak Chae-Hun by Kyodo News agency. Pak's nationality was registered as "Korean", meaning he has ancestral roots on the Korean peninsula, according to Suzuki. He added that Pak is suspected of using a credit card which he obtained illegally to make purchases from an online shopping company in Tokyo, Suzuki said. Pak is a former associate professor at the pro-Pyongyang Korea University in Tokyo and was engaged in espionage activities aimed at spreading North Korean ideology in South Korea and China, Kyodo reported. He is suspected of having purchased six computer equipment items online, the report said, adding that police found written instructions and encrypted e-mail messages from North Korea's spy agency on his confiscated computer. Other local media carried similar reports, saying Pak was active in South Korea from around 2000 when he was recruited by Pyongyang's intelligence agency known as "Bureau 225". North Korean spies have long been believed to be active in Japan. Pyongyang admitted in 2002 that it had kidnapped 13 Japanese in the 1970s and 1980s to train its spies in Japanese language and customs. Five of the abductees were allowed to return to Japan, but Pyongyang has insisted, without producing solid evidence, that the eight others are dead. The issue is a highly charged one in Japan, where there are suspicions that perhaps dozens of other people were abducted.