Photo/IllutrationTomomasa Nakagawa (Asahi Shimbun file photo)

A former executive of the Aum Shinrikyo cult who helped manufacture the sarin gas that killed 13 people and sickened more than 6,000 on the Tokyo subway system in 1995 has published a memoir.

In it, Tomomasa Nakagawa, 54, a former medical doctor and now death-row inmate, reveals the method used by the cult to manufacture the deadly nerve gas and also discusses former Aum leader Shoko Asahara, whom he cared for.

“He was a criminal before (being regarded as) a religious leader in that he transformed a religious organization into a criminal enterprise,” Nakagawa noted about Asahara, whose real name is Chizuo Matsumoto.

Matsumoto, 61, is also on death row.

Nakagawa published the memoir in the November issue of Gendai Kagaku (Chemistry Today), urged by Anthony Tu, professor emeritus at Colorado State University and an authority of toxicology.

Tu, who wrote a book on the subway attacks and also a 1994 sarin attack in Matsumoto, Nagano Prefecture, that killed eight people and sickened about 600, has interviewed Nakagawa many times.

The cultist, whose death sentence was finalized in 2011, was involved in both sarin atrocities and also the abduction and murders of anti-Aum lawyer Tsutsumi Sakamoto and his family members in 1989.

At the beginning of the memoir, whose main theme was “Why was (Aum) able to manufacture sarin?” Nakagawa apologizes to victims of the series of crimes committed by Aum cultists.

As for Asahara's skill as a leader of yoga and meditation sessions, Nakagawa writes, “His capability was extremely high."

“There were no people who joined Aum to commit murders. Including me, those who put absolute trust in Asahara in the fields of yoga and meditation became involved in the (fatal) incidents,” Nakagawa recalls.

He also reveals the chemical formulas he says were used to manufacture the sarin, which the cult began producing in around 1992.

In January 1995, the media reported that police suspected Aum was behind the sarin attack in Matsumoto. The gas was sprayed in a residential area in June the previous year.

Aum members hurriedly disposed of several hundreds of tons of sarin and other chemical substances to prevent police from finding the stockpile, Nakagawa writes in the memoir.

“All of us were poisoned by sarin (while doing that). I was just about able to stand,” he recalls.

The sarin attacks on the Tokyo subway system were carried out on March 20, 1995.

Nakagawa was one of the cultists who manufactured it, utilizing chemicals that were not disposed of in the January clearing out.

Nakagawa said in court that Yoshihiro Inoue, 47, also a former Aum executive and a death-row inmate, was responsible for storing the chemicals.

However, in a court ruling on a different former executive of Aum, it was stated keeping the chemicals was Nakagawa's job.

“Whatever the reason, terrorism is always intolerable,” the memoir reads.

It concludes with, “The background (of the act) of joining dangerous religious or terrorist organizations and the background (of the act) of carrying out terror acts after joining those organizations should be distinguished.”

Minoru Kariya, 56, the eldest son of Kiyoshi, a notary public who was also abducted and killed by Aum in 1995 at the age of 68, said that many bereaved families still have questions after listening to the remarks made by various Aum members in court.

“If former executives of Aum release their memoirs, it could help clarify the facts (of the series of crimes committed by the organization),” said Kariya, who has repeatedly interviewed Inoue and Nakagawa.