A top Metropolitan Police Department investigator probing last year's shooting of Japan's police chief was fired yesterday because he failed for five months to report that an officer who belonged to the Aum Shinri Kyo religious cult had confessed to the ambush. The 31-year-old officer confessed to shooting National Police Agency head Takaji Kunimatsu in March 1995 on the orders of senior Aum official Yoshihiro Inoue, in a bid to derail the police investigation into the cult's sarin gas subway attack 10 days earlier. The officer, whose name has not been released, first confessed to senior police officials in May but there was no follow-up investigation, according to internal letters and memos made public yesterday. 'I couldn't believe my ears,' said Mr Kunimatsu, announcing that Masaru Sakurai, head of the Metropolitan Police Department's Public Security Bureau, would be replaced immediately by Norikiyo Hayashi, director-general of the Organised Crime Control Department. But he tried to deflect criticism of the agency as a whole by saying there was a lot of confusion over what was being said and what could be verified. 'The officer in question has contradicted himself a number of times since May,' he said. The officer has still not been formally charged with the shooting, due to the inconsistencies in his statements and the fact that no evidence has been found to substantiate his story, news reports said. A senior official of Prime Minister Ryutaro Hashimoto's Liberal Democratic Party, Masakuni Murakami, was quoted by Jiji Press as telling a meeting of the party's leaders that the metropolitan police should be blamed for their 'secretiveness.' 'Without a tip-off letter, the confession might have never come to light. It's a grave problem of law and order,' Mr Murakami reportedly said. The officer's confession to the assassination attempt was made public only last week after a tip-off to the media, believed to be from an insider. Mr Kunimatsu, the target of the shooting, was seriously wounded but has since recovered. He told the Asahi Shimbun that Mr Sakurai had appeared to be 'hesitant' in leading the investigation.