A man who had threatened attacks on disabled people went on a knife rampage Tuesday at the care centre where he previously worked, leaving 19 people dead in Japan's worst mass killing for decades.
The 26-year-old had been hospitalised earlier this year after delivering a letter to parliament in which he threatened to kill hundreds of the disabled.
He turned himself in at a police station, carrying bloodied knives and admitting to officers: "I did it."
"The disabled should all disappear," he reportedly said.
Authorities identified the attacker as Satoshi Uematsu and said he had worked at the care centre for mentally disabled people in Sagamihara, a city of more than 700,000 people west of Tokyo, until February.
They said the attack began in the early hours of the morning when Uematsu broke a first-floor window to get in. Public broadcaster NHK reported that he tied up one caregiver before starting to stab the residents.
A doctor at one of the hospitals where victims were taken said some had deep wounds to the neck.
"The patients are very shocked mentally and they cannot speak now," the doctor told NHK.
A fleet of ambulances, police cars and fire trucks converged on the Tsukui Yamayuri-en centre, a low-rise complex nestled against forested hills, which was cordoned off and draped with yellow "Keep Out" tape.
Japan has one of the lowest rates of violent crime in the developed world and the mass killing is believed to be the nation's worst since 1938, when a man armed with an axe, sword and rifle went on a rampage that left 30 people dead.
"This is a very tragic, shocking incident in which many innocent people became victims," top government spokesman Yoshihide Suga told a press conference.
Japanese media said that in February Uematsu had delivered a letter to the speaker of Japan's parliamentary lower house, threatening to attack two care centres including Tsukui Yamayuri-en and kill 470 residents.
He said it would launch a "revolution" that would "stimulate the economy and prevent World War III".
In the letter he also presented his vision of a society in which the seriously handicapped could be euthanised with the approval of family members since "handicapped people only create unhappiness".
The ramblings brought him to the attention of Tokyo police, who informed Sagamihara authorities that he was a potential threat, a city official told AFP.
Private broadcaster NTV reported that Uematsu told police he had been fired from his job, though officials said only that he left the position.
'Normal, nice boy'
Uematsu was hospitalised on February 19, reportedly the same day he left his job, but was discharged 12 days later when a doctor deemed he was not a threat, the Sagamihara city official said.
While hospitalised Uematsu was diagnosed as suffering from paranoia as well as being dependent on cannabis, he added.
"I feel pain as it's said there was no problem, but that was the decision at that time," said Eiji Yagi, another Sagamihara official in charge of the city's mental health welfare section.
Police said they received a call from the centre around 2:30 am — about 20 minutes after the assault began — reporting that a man armed with knives had entered the facility. They said he turned himself in half an hour later.
Fire department spokesmen told AFP that the dead were nine men and 10 women aged from 18 to 70, and another 25 people were wounded, 20 of them seriously.
People in Uematsu's neighbourhood, about a 10-minute walk from the crime scene, expressed disbelief.
He was a "normal, nice boy" who always smiled and offered a greeting, said next-door neighbour Akihiro Hasegawa.
"This is unbelievable," the 73-year-old told AFP, adding that Uematsu lived in the house with his parents until they moved out four or five years ago.