Top members of the AUM Shinrikyo cult, including those involved in the March 1995 shooting attack on a police chief, gathered at a cult facility in Yamanashi Prefecture, where its founder Shoko Asahara was hiding, shortly before the incident, police said.
The shooting of then National Police Agency chief Takaji Kunimatsu occurred about a week after police raided the cult's facilities across the country over its sarin gas attack on Tokyo subway trains and other crimes.
Metropolitan Police Department (MPD) investigators suspect that Asahara summoned his top aides to plot the attack on Kunimatsu in a bid to obstruct police investigations into the cult.
Local police confirmed that Kiyohide Hayakawa, 54, Tetsuya Uemura, 49, and Satoru Hashimoto, 37, were in the AUM building in the village of Kamikuishiki in the predawn hours of March 30 where Asahara was hiding at the time.
Later in the day, Kunimatsu was shot in front of his condominium in Arakawa-ku, Tokyo, and suffered serious wounds that took 18 months to heal.
Toshiyuki Kosugi, 39, a former senior officer at the MPD who previously belonged to the cult, told investigators that he met Hayakawa, Uemura and Hashimoto near the scene. Kosugi was arrested Wednesday over the shooting case.
Investigators suspect that Hayakawa played a leading role in the shooting, and that Hashimoto pulled the trigger of the gun, while Uemura acted as a "dummy" by posing as the gunman and fleeing the scene by bicycle.
Hashimoto, who had been in Russia and Yugoslavia since early February 1995, and Hayakawa, who had been in Moscow, returned to Japan on the same flight on March 22 -- the day when police launched raids on the cult facilities.
Police also suspect that Hashimoto underwent shooting training in Europe and Asia between 1992 and 1995.