The prosecution on Thursday demanded the death penalty for the man who has admitted to the 2019 arson attack on Kyoto Animation Co. that killed 36 people, while his defense sought an acquittal or lesser sentence, citing what they said was his mental incompetence.

In seeking capital punishment for Shinji Aoba, 45, in the lay judge trial at the Kyoto District Court, a prosecutor said his conduct was "premeditated, extremely dangerous and truly cruel, having a significant impact on society."

Aoba entered Kyoto Animation's Studio 1 on July 18, 2019, at around 10:30 a.m. and used gasoline to start a fire, killing 36 and seriously injuring 32 of the 70 employees and others in the building, according to the indictment.

Photo taken on Dec. 7, 2023, shows Kyoto District Court in Kyoto. (Kyodo)

The studio, often referred to as "KyoAni," is known internationally for producing a number of animation works, including "K-On!" and "The Melancholy of Haruhi Suzumiya."

The focus of the trial over one of Japan's worst-ever mass murder cases is whether Aoba is legally competent. The ruling is scheduled to be handed down on Jan. 25 next year.

In their final argument, the defense for Aoba referred to what they called the brutality of capital punishment and said Aoba was mentally incompetent at the time of the attack.

"The death penalty should not be chosen for Mr. Aoba," one of his lawyers said.

File photo shows smoke rising from Kyoto Animation Co.'s Studio 1 in Kyoto on July 18, 2019, following a deadly arson attack. (Kyodo)

The prosecution acknowledged that Aoba harbored delusions, wrongly believing a novel he entered in a contest held by Kyoto Animation had been plagiarized by the firm, but said his delusions had limited impact on his behavior and did not constitute a reason to avoid the maximum sentence.

"The victims bore no fault and the horror and despair of being exposed to a hellish situation is indescribable," the prosecutor said, adding, "The degree of disregard for life is profound."

The prosecutor also called the defendant's motive "completely irrational" and "utterly selfish," saying he had shifted the blame for his unsuccessful life onto Kyoto Animation.

In his closing statement, Aoba said, "I have answered questions to the best of my ability. There is nothing more to add at this moment. That's all."

The defendant has admitted to the attack, saying he undertook it due to his belief Kyoto Animation stole the ideas in his novel. During the trial on Wednesday, he apologized to the victims' families for the first time, saying, "I am sorry."

During Thursday's trial, the 51-year-old husband of victim Shoko Terawaki, who died at the age of 44, said, "I wish for the most severe punishment to be imposed."

A lawyer representing the family of another victim said, "There is no room for any choice other than the death penalty."

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