Satoshi Uematsu

Satoshi Uematsu (, 1990- ) was a Japanese mass murderer, a perpetrator of 2016 that killed 19 people. He was a 26-year-old (at the time of the incident) man. 
Incident.
Uematsu used to work at the care home "Tsukui Yamayuri En" (津久井やまゆり園). He resigned from working at the facility in February 2016 after having been employed there for over three years. 
In February 2016, Uematsu appealed by letter for the legalization of ending the lives of those with multiple disabilities in cases where it was requested by their guardians, and asked for Tadamori Oshima's assistance in delivering his message to Japanese Prime Minister Shinzō Abe. In it, he wrote, "I envision a world where a person with multiple disabilities can be euthanised, with an agreement from the guardians, when it is difficult for the person to carry out household and social activities." He also wrote that the killings of the disabled would be "for the sake of Japan and world peace" as well as to benefit the global economy and prevent World War III.
In 26 July 2016, Uematsu killed 19 people at "Tsukui Yamayuri En" by Knives. On 16 March 2020, Uematsu was sentenced to death by the Yokohama District Court, having previously said he would not challenge any verdict or sentence. On 30 March 2020, his death sentence was finalized as he withdrew automatic appeal to the upper courts.