It was one of Japan’s deadliest mass killings since the end of World War II.
Uematsu, now aged 30, broke in to the Tsukui Yamayuri-en facility in Sagamihara, a city west of Tokyo, where he used to work.
He tied up two members of staff, and then went from wing to wing, floor by floor, killing patients, officials said at the time. The facility was home to 149 residents, ranging in age from teenagers to those in their 70s, at the time.
Around an hour after the attack began, Uematsu turned himself in at a local police station, carrying a bloodstained knife and cloth, officials said.
“I am aware that this is an outrageous thing to say,” he wrote, adding that he dreamed “of a world where disabled people with severe difficulties socializing as well as severe difficulties at home are allowed to be peacefully euthanized.”
Uematsu was later committed to an institution to prevent him from “harming others,” Japanese national broadcaster NHK reported, and resigned from his job.
But when he was discharged from the institution in March 2016, the hospital failed to inform the care center, although extra security cameras had been set up around the facility.
Uematsu began working at the care home in 2012 and had no specific problems with the patients, a prefectural official said following the attack.
Former colleagues said he was personable and good with children and neighbors were shocked to hear of his involvement in the incident. However, Uematsu also had run-ins with the police, according to NHK. In 2015, he had fought and injured a man at a suburban Tokyo train station.
Japan and violence
The 2016 attack sent shockwaves through Japan, where mass killings are rare.
In June 2001, eight children were killed when a former janitor entered an Ikeda elementary school in Osaka and began stabbing students at random.
In June 2008, a man ran over a group of people with his truck and then stabbed 18, killing seven, in Tokyo’s famous Akihabara gaming district.
Chie Kobayashi , Euan McKirdy and James Griffiths contributed to this report.