At least 19 residents of a disabled care facility in Sagamihara, Kanagawa Prefecture, were killed and 23 have been injured after an early morning attack by a knife-wielding man, the Japanese broadcaster NHK reports.

According to police, 26-year-old Satoshi Uematsu, the former employee of the Tsukui Yamayuri-en facility which is located to the south of Mt. Takao, entered the building through a window with a bag full of knives and began stabbing residents at approximately 2:30am, local time. He then turned himself into police less than an hour after the attacks. According to the Guardian, he has been arrested on charges of attempted murder and trespassing. A local resident who lives next to the facility told NHK that a man with blond hair and dressed in black clothes had been arrested.

According to the Asahi Shimbun as quoted in the Japan Times, Uematsu told the police that “I want to get rid of the disabled from this world,” while the New York Times quotes other news sources reporting that Uematsu screamed “All the handicapped should disappear!” during his attack.

According to Twitter user Durf Japanese papers have reported that Uematsu tweeted the following picture after the attack:

[Translation: Let there be peace in the world. beautiful Japan!!!!!!]

In an Associated Press story, it was revealed that, in February, Uematsu had tried to deliver a letter to the Speaker of the lower house of Parliament in which he called for all disabled people be put to death through “a world that allows for mercy killing.” He also boasted that he had the ability to kill nearly 500 disabled people in what he called a “revolution.” He wrote the letter after he was let go of his job at Tsukui Yamayuri-en. Tokyo police got the letter and passed it on to local police in Sagamihara, and Uematsu was temporarily hospitalized after local authorities followed up.

This is one of the worst mass killings in Japan for several decades. Although gun violence is extremely rare in Japan because of strict gun laws, mass attacks like this have taken place in the past, but not at this scale. A man killed eight children and injured 15 in a knife attack at an elementary school in Osaka Prefecture, while in 2008, a man drove a truck into a crowd and went on a rampage with a knife in Tokyo’s Akihabara neighborhood, killing seven and wounding 10.

A total of 149 residents, ranging in age from 19 to 75 and suffering from a wide range of disabilities, live at Tsuki Yamayuri-en (Tsukui Mountain Lily Garden) on a permanent basis, and it houses a staff of eight during the overnight period. The large, three hectare (7.6 acre) compound has a pool and other recreational facilities for the the residents. Sagamihara is one of Kanagawa’s largest cities, and is located about 45 km to the west of Tokyo. The care facility is located in the northwest area of the city.

Image: Screenshot from NHK (at time of video broadcast, 15 had been confirmed dead at Tsukui Yamayuri-en)