TAIPEI (Kyodo) -- Anthony Tu, a Taiwan-born toxicologist known for aiding investigations into sarin attacks involving the AUM Shinrikyo cult in Japan, has died in Hawaii, his family said Wednesday. He was 94.

The professor emeritus at Colorado State University of the United States assisted Japanese authorities in analyzing sarin nerve gas used for deadly attacks in Matsumoto, Nagano Prefecture, in 1994 and on the Tokyo subway system in 1995.

The Colorado resident likely died last Friday at a Honolulu hotel, his family said. Born in 1930 in Taiwan, then under Japanese colonial rule, Tu earned a doctorate from Stanford University in 1961 and became a leading expert on chemical and biological weapons.

Tu repeatedly met with former senior AUM member Tomomasa Nakagawa before he was executed in 2018 for his role in the Tokyo sarin attack and other assaults involving highly lethal VX nerve agent.

He jointly published a research paper with Nakagawa on the VX nerve agent after Kim Jong Nam, the estranged half-brother of North Korean leader Kim Jong Un, was assassinated with the substance in Malaysia in 2017.

A fluent Japanese speaker, he also served as a visiting professor at the Chiba Institute of Science. In 2009, he received the Order of the Rising Sun, Gold Rays with Neck Ribbon, in recognition of his contributions to crisis management studies in Japan.