At two in the morning on a Tuesday in July 2016, most of the residents of Tsukui Yamayuri-en were asleep. They were adults with severe intellectual and physical disabilities — some unable to speak, some unable to move without help — living in a residential care facility tucked into the hills outside Sagamihara, about forty kilometers southwest of Tokyo. It was a large institution, home to roughly one hundred and fifty people. It was supposed to be the safest place they could be.

The man who arrived that night was not a stranger. He had worked here for over three years. He knew the building. He knew which doors the keys opened. He knew where the staff stood and where the residents slept.

In the next hour, nineteen people would be killed. And when it was over, the man responsible would turn himself in — carrying a bag of blood-stained knives — and tell the world, without apology and without remorse, exactly why he had done it.

Sagamihara Care Home Stabbings · 2016-07-26 · Tsukui Yamayuri-en, Midori Ward, Sagamihara, Kanagawa, Japan

In the autumn of 2017, a twenty-seven-year-old man in a quiet Japanese city was killing people — one at a time, over ten weeks — and almost nobody noticed. The bodies were in his apartment the whole time. Nine of them. Strangled, dismembered, stored in cooler boxes a few feet from where he slept.

What made it possible was a single tool: Twitter.

He found his victims the same way anyone finds anything on social media — by searching a hashtag. The hashtag was "shinitai." In Japanese, that means "I want to die." He wasn't searching it to help people. He was searching it to hunt them. This is the story of Takahiro Shiraishi, and the nine people he murdered in Zama.

Zama Serial Killings (Twitter Killer) · 2017-08-01 to 2017-10-27 · Zama, Kanagawa, Japan

It was ten in the morning on a Thursday in June. Children in neat school uniforms were sitting at their desks, just like every other day. Parents had already dropped them off. Teachers were working through the morning lessons. The school was the kind of institution families aspired to send their children to — attached to Osaka Kyoiku University, one of the most prestigious elementary schools in the region.

By 10:20 a.m., eight of those children were dead. Seven were girls. One was a seven-year-old boy. And the man who killed them had bought the knife less than an hour before.

This is the Osaka Ikeda School Massacre — Japan's deadliest school attack in recorded history.

Osaka Ikeda School Massacre · 2001-06-08 · Ikeda, Osaka Prefecture, Japan

It's New Year's Eve, 2000. Somewhere in the quiet western suburbs of Tokyo, a family of four is going to be murdered tonight.

The killer who does it will leave behind more physical evidence than almost any unidentified suspect in Japanese criminal history — DNA, fingerprints, clothing, his own belongings, even a biological sample from the bathroom. He will eat their ice cream. He will drink their tea. He will sit down at the father's computer. And then, some time before dawn, he will slip out of the house and vanish completely.

Twenty-five years later, he has never been identified. More than five million fingerprints have been compared. More than a million DNA samples checked. A reward worth twenty million yen — the largest in Japanese history — sits unclaimed. And the case has changed Japanese law forever, because a country that watched this happen refused to accept that a murderer could one day walk free on a technicality.

This is the story of the Setagaya Family Murder.

Setagaya Family Murder · 2000-12-30 · Kamisoshigaya, Setagaya, Tokyo, Japan

On the morning of May 27, 1997, teachers and students arriving at Tomogaoka Junior High School in Kobe found something waiting for them at the school gate. Something that would stop an entire nation cold.

There, placed with apparent deliberateness, was the severed head of an eleven-year-old boy. Stuffed in his mouth was a handwritten note, signed with a name no one recognized: "Seito Sakakibara." The note promised that this was only the beginning.

Japan had not seen anything like it. The person who left that note — who had committed these crimes — was not a shadowed adult with a long criminal history. He was a fourteen-year-old junior high school student. He attended the very school whose gate he had chosen for this display.

This is the Kobe child murders. And decades later, it remains one of the most disturbing cases in modern Japanese history.

Kobe Child Murders (Sakakibara Case) · 1997-02-10 to 1997-05-27 · Suma Ward, Kobe, Japan

It's 8 o'clock in the morning in Tokyo. The trains are packed the way Tokyo trains always are during rush hour — shoulder to shoulder, silent, nobody making eye contact. Office workers, students, government clerks, station attendants just doing their jobs.

And then, on five separate trains rolling toward the center of the city, people start collapsing. Their vision goes dark. They can't breathe. Some fall to the floor, convulsing. Others stumble onto platforms and lie there, unable to move, not understanding what is happening to them.

By the time anyone figures out it's a nerve agent, more than five thousand people have been poisoned. Thirteen will die. And the men responsible are already in getaway cars, speeding away from stations where subway workers are trying to pick up leaking bags of liquid with their bare hands — not knowing what those bags contain.

This is the story of the Tokyo subway sarin attack. March 20, 1995. The day a doomsday cult brought chemical warfare to the morning commute.

Tokyo Subway Sarin Attack · 1995-03-20 · Tokyo Metro, Hibiya / Chiyoda / Marunouchi lines, Tokyo, Japan

Noon, on a bright Sunday in the middle of Tokyo. The most famous electronics district in the world has just closed its main street to traffic, the way it does every weekend, so that thousands of people can walk down the middle of the road in the sun. It's supposed to be the safest kind of crowd there is.

In about three minutes, seven of those people will be dead.

And here's the part that stays with you: the man who killed them had been typing out his plan, in public, on his phone, for anyone to read — right up until twenty minutes before he did it. Nobody stopped him. This is the story of the Akihabara Massacre.

Akihabara Massacre · 2008-06-08 · Akihabara, Chiyoda, Tokyo, Japan