The former police sergeant who confessed last spring to gunning down National Police Agency head Takaji Kunimatsu in Tokyo in March 1995 has claimed he carried out the ambush after taking a white pill given to him by Yoshihiro Inoue, a senior Aum Shinrikyo figure, police sources said Feb. 6.

Toshiyuki Kosugi, 31, who was fired last fall from the Metropolitan Police Department and who was also a former Aum follower, reportedly said that when Inoue ordered him to shoot the NPA chief, he first thought there was no way he could bring himself to attack his boss. Further information about the nature of the pill was not provided.

Inoue was the cult's intelligence chief up until his arrest. The MPD is interrogating Kosugi about his involvement in the shooting. It believes his statements are specific and detailed to the extent that no one else but the gunman himself could have made such admissions.

Kosugi was fired in disgrace by the MPD last year and was recently charged with violating the Local Civil Service Law. Investigative authorities, in cooperation with the Tokyo District Public Prosecutor's Office, are considering taking steps to charge him with attempted murder in connection with the Kunimatsu shooting, the sources said.

Kosugi has reportedly said he fired the second and third rounds in double-action. Such a revolver can be fired by merely pulling the trigger, and without first cocking back the hammer. He claims the fourth shot missed Kunimatsu. His statement corresponds to what detectives believe actually occurred. According to a police inspection of the scene, the first three bullets hit Kunimatsu and the fourth missed.