The facility after the attack, July 26

SAGAMIHARA, Japan — A knife-wielding man broke into a facility for the disabled in a small town near Tokyo early on Tuesday and killed 19 patients as they slept, authorities said, Japan’s worst mass killing in decades.

At least 25 other residents were wounded in the attack at the Tsukui Yamayuri-En facility in Sagamihara town, about 25 miles southwest of Tokyo.

“This is a very heart-wrenching and shocking incident in which many innocent people became victims,” Chief Cabinet Secretary Yoshihide Suga told a regular news conference in Tokyo.

The suspect was a 26-year-old former employee of the facility who gave himself up to police. The man, Satoshi Uematsu, said in letters he wrote in February that he could “obliterate 470 disabled people”, Kyodo news agency reported.

He said he would kill 260 severely disabled people at two areas in the facility during a night shift, and would not hurt employees.

“My goal is a world in which the severely disabled can be euthanized, with their guardians’ consent, if they are unable to live at home and be active in society,” Uematsu wrote in the two letters given to the speaker of the lower house of parliament, Kyodo reported.

Uematsu was committed to hospital after he expressed a “willingness to kill severely disabled people”, an official in Sagamihara told Reuters. He was freed on March 2 after a doctor deemed he had improved, the official said.

Uematsu lived near the facility, and a neighbor described him as a polite, young man who always greeted him with a smile.

“It would be easier to understand if there had been a warning but there were no signs,” said Akihiro Hasegawa, 73. “We didn’t know the darkness of his heart.”

The suspect apparently began changing about five months ago, said Yuji Kuroiwa, the governor of Kanagawa prefecture, where the facility is located.

“You could say there were warning signs, but it’s difficult to say if this could have been prevented,” he told reporters.

“This was not an impulsive crime … He went in the dark of the night, opened one door at a time, and stabbed sleeping people one by one,” Kuroiwa said. “I just can’t believe the cruelty of this crime. We need to prevent this from ever happening again.”

Staff at the facility called police at 2.30 a.m. local time with reports of a man armed with a knife on the grounds, media reports said. The man wore a black T-shirt and trousers, the reports said.

The facility cares for people with a wide range of disabilities. The center had a maximum capacity of 160 people, including staff.

Japan has one of the lowest crime rates in the world and residents of Sagamihara said they were in shock. The last murder in the area was 10 years ago.

“This is a peaceful, quiet town so I never thought such an incident would happen here,” said Oshikazu Shimo, one of many residents of the town who gathered near the facility.

Taxi driver Susumu Fujimura said of the attacker: “He said ‘we should get rid of disabled people’ but he’s the worthless one.”