A Japanese man who went on a stabbing rampage at a facility for the mentally disabled, killing 19 people and injuring 25 others, appears to have been fuelled by hatred.
Satoshi Uematsu, 26, had been sacked from the unit and had reportedly sent a letter to Parliament outlining his plan.
The 40-minute attack in the early hours of yesterday was the deadliest mass killing in Japan in decades.
Twenty of the wounded were seriously injured.
Uematsu drove up in a black car, carrying several knives to the Tsukui Yamayuri-en facility in Sagamihara, 30 miles (50km) west of Tokyo, according to security camera footage broadcast on television news programmes.
He broke in by shattering a window at 2:10am, according to a prefectural health official, and then set about slashing the patients’ throats.
Details of the attack, and whether the victims were asleep or otherwise helpless, were not immediately known, although a cryptic letter he sent to Japan’s Parliament in February gave a glimpse into Uematsu’s dark turmoil.
He calmly turned himself in about two hours after the attack, police said.
Tsukui Yamayuri-en, which means mountain lily garden, was a facility Uematsu knew well, having worked there since 2012 until he was fired in February.
He knew the staffing at the unit for about 150 patients would be down to just a handful in the early hours of the morning, Japanese media reports said.
Not much is known yet about his background, but Uematsu once dreamed of becoming a teacher. In two group photos posted on Facebook, he looks happy, smiling widely with other young men.
“It was so much fun today. Thank you, all. Now I am 23, but please be friends forever,” a 2013 post says.
But somewhere along the way, things went awry.
Uematsu began to tell people around him that disabled people needed to be killed.
In February, he tried to hand-deliver a letter he wrote to parliament’s lower house speaker demanding all disabled people be put to death through “a world that allows for mercy killing”, the Kyodo news agency and TBS TV reported.
Uematsu boasted in the letter that he had the ability to kill 470 disabled people in what he called “a revolution”, and outlined an attack on two facilities, after which he said he would turn himself in.
He also asked he be judged innocent on grounds of insanity, be given 500 million yen (about £3.6 million) in aid and plastic surgery so he could lead a normal life afterwards. The letter was reprinted by Kyodo after the attack.
“My reasoning is that I may be able to revitalise the world economy and I thought it may be possible to prevent World War III,” the letter says.
The letter, passed to Tokyo police, included Uematsu’s name, address and telephone number, and reports of his threats were relayed to local police where Uematsu lived, Kyodo said.