Makoto Hirata, a former Aum Shinrikyo executive serving time in Shizuoka, says he has “no special feelings” about the execution last month of Shoko Asahara, the former head of the now-defunct doomsday cult that carried out the deadly sarin attack on the Tokyo subway system in 1995.

“I was lost for words” upon hearing that 12 other former senior Aum members had been hanged, Hirata, 53, said in a prison interview in the city.

Hirata, who was suspected of involvement in several Aum-related crimes, turned himself in to the police on Dec. 31, 2011, after all criminal trials on cases linked to the cult, including the March 1995 sarin attack, which killed 13 people and injured over 6,000 others, had been completed.

At his trial, Hirata called for the 12 former senior Aum members, excluding Asahara, whose real name was Chizuo Matsumoto, not to be executed.

The Justice Ministry executed the 13 last month. Seven, including Asahara, 63, were hanged on July 6 and the other six on July 26. The executions purged death row of all Aum members.

“I doubt whether it was really good to execute the members, even apart from my personal feelings for them,” Hirata said, emphasizing that lessons learned from Aum’s crimes should be incorporated into future counterterrorism measures.

Asked whether his surrender at the end of 2011 affected the timing of the executions, Hirata said: “If I didn’t show up, the executions could have been carried out earlier or might have been put off. I have no idea about it.”

Three Aum successor groups, including Aleph, are currently active.Noting that new members of Aum or its successors have never met Asahara, Hirata said he thinks Asahara is “a fictitious person” and merely a symbol for them now.

“I think the execution (of Asahara) had little impact” on members of the successor groups, he said.

In March 2014, the Tokyo District Court sentenced Hirata to nine years in prison on charges including abduction and confinement related to his involvement in cases that included the kidnapping of a Tokyo notary public. His sentence was finalized by the Supreme Court in January 2016.