TOKYO -- A man accused of carrying out a deadly arson attack on a Kyoto Animation Co studio four years ago admitted the charges in the indictment, in the first hearing of his trial at Kyoto District Court on Tuesday.

Shinji Aoba, 45, from Saitama Prefecture, north of Tokyo, faces murder and four other charges over the attack on the No. 1 studio of the animation powerhouse also known as KyoAni in Kyoto on July 18, 2019, which left 36 people dead and 32 others injured.

"I didn't imagine that so many people would lose their lives, and I now think that I went too far," Aoba said at the outset of the lay judge trial, admitting that he carried out the attack.

The defense team said Aoba was suffering from delusions and believed he was fighting back against a "dark figure," arguing that even if he is convicted, he should be given a reduced sentence because of his state of diminished capacity.

His lawyers also said the studio's structure may have had led to the large number of fatalities.

The prosecutors said Aoba wrongly believed that KyoAni had plagiarized a novel he had entered into a contest run by the firm and that he was under surveillance by the authorities. But they said he was not controlled by such delusions and can be held fully responsible for the attack on the studio.

The prosecutors indicted him in December 2020, claiming after conducting a psychiatric evaluation that he can be held criminally responsible for his actions, despite his documented history of mental illness.

After Tuesday's first hearing of the lay judge trial, 23 more sessions are expected to follow before the ruling is handed down on Jan 25, 2024.