A former employee of a center for the disabled in a Tokyo suburb broke into the building and killed 19 people with a knife early Tuesday, local officials said.
The suspect, Satoshi Uematsu, 26, went on a rampage around 2:20 a.m. in Sagamihara, a town an hour west of Tokyo, according to the authorities in Kanagawa Prefecture. Twenty-five people were reported wounded, all but one of them seriously.
Just half an hour after the attack, Mr. Uematsu turned himself in at a nearby police station and was charged with attempted murder. Additional charges were expected. The attack was the worst mass killing in Japan in decades. The country has one of the lowest crime rates in the world.
All of the dead, nine men and 10 women, were residents of the center. They ranged in age from 18 to 70 and were found in both buildings on the site.
According to Kanagawa Prefecture officials, Mr. Uematsu entered the building by breaking a first-floor window with a hammer. He was carrying a bag of knives. He later told the police that “all the handicapped should disappear.”
The center, Tsukui Yamayuri-en, which is operated by the prefecture, has 149 long-term residents with mental disabilities. Other patients stay overnight for short periods. Some have physical disabilities as well. It offers services like meals and baths, as well as arts activities.
NHK, the Japanese public broadcaster, reported that eight staff members and a security guard were on duty at the time of the attack. Some staff members told the police that they had been tied up. TV Asahi reported that 16 surveillance cameras had been installed at the center.
Mr. Uematsu worked at the center from December 2012 until last February, Kanagawa Prefecture officials said. It was not clear why he had left.
NHK reported that the local authorities had Mr. Uematsu committed to a hospital in February, days after he delivered a letter to a politician’s residence in Tokyo in which he threatened to kill hundreds of disabled people “for the sake of Japan” and urged legal changes that would allow the severely disabled to be euthanized. But he was released on March 2, after doctors concluded that he was not a danger to others, the broadcaster said.
According to NHK, Mr. Uematsu gave the handwritten letter to security officers at the residence of the speaker of the lower house of Parliament on Feb. 15, after being turned away the previous day. The Tokyo police notified their counterparts in the Sagamihara area about Mr. Uematsu’s letter on the same day, NHK said.
“My aim is a world where people with multiple disabilities who have extreme difficulty living at home or being active in society can be euthanized with the consent of their guardians,” Mr. Uematsu wrote in the letter, according to the report.
A Twitter account that appeared to be Mr. Uematsu’s included bizarre posts saying that Japan was being destroyed by AIDS and radiation poisoning. The most recent post, including a photo of Mr. Uematsu about 30 minutes after the attack began, reads, “May the world be peaceful,” and, in English, “Beautiful Japan!”
Outside the police station in Sagamihara, a black car sat in the parking lot, covered in a blue tarp. The local news media had reported that it was the car Mr. Uematsu drove to the station for his confession, broadcasting images of a bloody steering wheel and plastic ties scattered on a seat. Police officers outside the station would not confirm that it was his vehicle.
The back bumper was broken and had an English-language sticker that read: “I’m not driving too slow. You’re speeding.”
Kiyoshi Nakatsuka, 73, the vice chairman of the parents’ group for residents at the center, said his son, in his 40s, was lucky enough to escape the killings, NHK reported. Mr. Nakatsuka said many other members of the family were waiting to hear about their relatives. He had never heard of Mr. Uematsu, or of any problems with other employees, he said.
Mr. Uematsu lived nearby in a large, cream-colored concrete house on a hill with overgrown weeds. He had lived with his parents until they moved away, neighbors said. A pile of trash inside the home was visible through one of the windows, and a garden shed next to the house was half open.
Akihiro Hasegawa, 73, who lives next door, said he had often seen Mr. Uematsu playing with neighborhood children who recognized him from a local school where he trained as a teacher. He was following in the footsteps of his father, who taught art at an elementary school.
Mr. Hasegawa recently saw Mr. Uematsu shirtless outside the house, taking in the sun, and observed tattoos on his chest and back.
Another neighbor, Mitsuo Kishi, 76, agreed that Mr. Uematsu was always friendly. “I never imagined he was the kind of guy who would commit such a crime,” Mr. Kishi said.
“My granddaughter always said he was a good teacher,” he added.
Set in the Tanzawa Mountains, Sagamihara is a popular summer destination for hikers and other visitors drawn to its large, dam-created lake and campsites and artists’ studios.
“It is really scary,” said Isoko Otsuka, 85, who lives across the street from the police station and often visited the center as a volunteer. “It is unimaginable that this would happen in such a quiet countryside town.”
The town last made international news in 2012, when one of the suspects in the 1995 poison gas attack on the Tokyo subway system was arrested there.
Naoko Kikuchi, one of the most wanted people in Japan for her involvement in the attack, which killed 13 people and injured thousands, had been hiding in the town under the name Chizuko Sakurai.
Japan had just 0.3 murders per 100,000 people in 2011, according to United Nations data. The rate in the United States in the same year was more than 10 times as high, at 4.7.