A man believed to be detained in North Korea entered the country as part of a group organized by a former leader of the Red Army faction, according to sources close to Tokyo-Pyongyang relations. The sources said a five-member group led by Takaya Shiomi, 60, left Narita airport Nov. 30 and arrived in Pyongyang via Beijing the same day. With the exception of Takashi Sugishima, who according to North Korean news reports was detained earlier this month on charges of spying, all returned to Japan in early December, the sources said. On Thursday, the Foreign Ministry questioned Shiomi about the group's trip to North Korea, the sources said. Shiomi is a former leader of the Red Army faction, an ultraleftist group that gained worldwide attention for terrorism in the 1970s, including the 1970 hijacking of a Japan Airlines jetliner, which was forced to land in Pyongyang. The official (North) Korean Central News Agency identified Sugishima as a researcher for the Tokyo-based Japan Market Economy Institute. Takaaki Nabeshima, head of the institute, said Sugishima was a part-time worker.