Japan has been stunned and sickened by what the Guardian reports is the country's biggest mass killing since World War II: The murder of 19 people at a center for the disabled just outside Tokyo. Satoshi Uematsu, a 26-year-old former administrator at the Tsukui Yamayuri-En facility in Sagamihara, surrendered at a police station after the Tuesday morning rampage, in which victims with ages ranging from 19 to 70 were stabbed to death and another 26 people were injured, the BBC reports. The Kyodo news agency says Uematsu wrote to the speaker of Japan's House of Representatives in February, threatening to "obliterate 470 disabled people" during a night shift at the facility, which cared for people with a range of mental and physical disabilities, reports Reuters.
"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," wrote Uematsu, who allegedly attacked his victims as they slept after he broke into the center at around 2:10am. Kyodo says that in the letter, Uematsu also claimed killing the disabled would help the world economy and prevent World War III, the AP notes. Authorities say Uematsu was committed to a mental hospital after sending the letter and telling colleagues that he wanted to harm disabled people, but was released on March 2 after doctors decided he had improved. The Washington Post reports that an hour before the attacks, Uematsu tweeted what is believed to be a photo of himself, with the message: "Wishing for world peace. beautiful Japan!!!!!!"