Fusako Shigenobu, the arrested leader of the Japanese Red Army, has traveled to and from Japan eight times over the past three years using a false passport, investigative sources said Saturday.

Records detailed in the fake passport, seized by police in one of Shigenobu's hideouts, show that the 55-year-old leader of the extreme leftist group used Kansai International Airport for most of her visits to and departures from Japan.

The National Police Agency and the Osaka Prefectural Police have mounted a joint effort to track Shigenobu's movements in recent years in the belief that she was trying to establish a network of extreme leftists in the Kansai region.