Hideo Murai (村井 秀夫 Murai Hideo; December 5, 1958 – April 23, 1995) was a Japanese criminal and member of the Aum Shinrikyo cult and one of the perpetrators responsible for the Sakamoto family murder. He also helped plan the Tokyo subway sarin attack. Murai held a doctorate in astrophysics. He was reportedly the number three person in the Aum leadership, after Shoko Asahara and Kiyohide Hayakawa. He headed Aum Shinrikyo's Ministry of Science and Technology.
Source: “Hideo Murai”, English Wikipedia (CC BY-SA 4.0), excerpt