Japan’s top financial regulator, Tadahiro Matsushita, was found dead at his home in Tokyo on Monday, according to The Japan Times newspaper.
Police said they suspect the former financial services minister may have committed suicide.
Matsushita, who was 73, was a member of the People's New Party, the coalition partner of the ruling Democratic Party of Japan.
Bloomberg reported that Matsushita, who was appointed to the regulator post by Prime Minister Yoshihiko Noda in June, had promised to intensify the government’s probe into an insider trading scandal at Japan’s largest brokerage house, Nomura Holdings.
In July, Nomura's two top officials, Chief Executive Officer Kenichi Watanabe and Chief Operating Officer Takumi Shibata, resigned after regulators uncovered evidence that workers had leaked information on sales of shares that the company managed.