Death Row Defendant in Nagano Quadruple Killing Displays Disturbing Behavior, Citing Otherworldly Persecution

“The defendant is sentenced to death.”

As the presiding judge pronounced the death sentence, the defendant standing before the witness stand swayed slightly as he listened.

On October 14, the Nagano District Court handed down the death penalty to Masanori Aoki (34) of Nakano City, Nagano Prefecture, who was charged with murder and violations of the Swords and Firearms Control Law. In May 2023, Aoki killed two women who were out for a walk and two police officers using a knife and a hunting rifle. Afterward, he barricaded himself inside his home with the rifle but was apprehended about 12 hours later by surrounding police officers.

The lay judge trial began this September.

“The defense argued that at the time of the crime, Aoki was in a state of delirium and suffering from delusional symptoms. The victims’ families pleaded in court, saying, ‘We want to know about our loved ones’ final moments,’ but Aoki gave no answers. He invoked his right to remain silent more than 90 times.

Aoki spoke about his feelings only once during the trial. While apologizing — saying, ‘I’m sorry for hurting the victims’ — he also stated: ‘I have been persecuted by a being from another dimension and came here to receive the death penalty. I will never play again,’” said a judicial reporter from a national newspaper.

“I don’t mind standing out (or being an outsider).”

During the roughly 30-minute explanation of the verdict, Aoki reportedly fidgeted—rocking his body and picking at his nails—as the judge pronounced the death sentence.

FRIDAY had been reporting from the scene since immediately after the incident, gathering testimonies from local residents that reveal both the brutality of the attack and Aoki’s strange behavior.

“A woman came running toward me, screaming for help, her face pale with fear. A man was chasing her and stabbed her in the back with a large knife—twice, I think. Then he stabbed her in the chest a third time and calmly walked back toward his house. He was wearing camouflage clothes, a black mask, and sunglasses,” said one eyewitness.

The man described by the witness was Aoki. Born to a city councilor father and a mother who ran a gelato shop and flower art classes, Aoki was markedly different from his sociable parents.

“I never saw him hanging out with friends. He seemed perfectly fine being on his own—almost indifferent to being isolated,” recalled a high school classmate.

After graduating from a prestigious local public high school, Aoki spent a year preparing for college entrance exams and was admitted to a mid-level private university in Tokyo. However, as classmates suggested, he struggled to connect with others. Unable to adapt to city life, he dropped out and returned to his hometown.

I can’t have a conversation with them.”

“He worked at a fruit orchard in the neighboring town, but he hardly ever spoke. Even if you called out to him ten times, he would ignore you seven or eight of those. On the rare occasions he did respond to a greeting, it never turned into a conversation. Sometimes farm work was done in groups, but even then, he wouldn’t work alongside others—he’d just stand there alone. People who worked with him often ended up exasperated,” said a nearby resident.

It seems the only one Aoki truly interacted with was his dog.

“I once saw him around 7 p.m., racing down the road on his bicycle after coming back from the orchard. He had a medium-sized white dog with him, but it looked less like a walk and more like he was dragging it along. Since he didn’t socialize with people, maybe he treated the dog as his only companion. I’ve also seen him on his motorbike, making the dog run alongside,” another local resident recalled.

Aoki, who was said to struggle with human interaction and spent much of his time with his dog, had his defense team argue for leniency on the grounds of mental illness. Former Kanagawa Prefectural Police detective and crime journalist Taihei Ogawa explained:

“Right after the killings, Aoki tried to carry one of the female victims’ bodies into his own property. That shows an intent to conceal the crime. And notably, he didn’t harm his family. If he’d truly been in a state of insanity, it wouldn’t be strange if he’d attacked them as well.

After a three-month psychiatric evaluation, prosecutors concluded that Aoki was criminally responsible for his actions. From an objective standpoint, his mental condition cannot be considered grounds for a lighter sentence. The High Court’s decision will be closely watched.”

The defense, dissatisfied with the death sentence, has announced plans to appeal.