A man on trial over a fatal knife rampage at a care home for the mentally disabled near Tokyo in 2016 reappeared in court on Friday, two days after he was removed from the courtroom for trying to bite off his finger.

Satoshi Uematsu, 29, who on Wednesday admitted to killing 19 residents and injuring dozens more at the facility, wore mittens on the second day of his trial at the Yokohama District Court.

The high-profile case involving an attack targeting socially vulnerable individuals, combined with discriminatory remarks Uematsu has made against the disabled, has shocked Japanese society.

Uematsu apologized when Presiding Judge Kiyoshi Aonuma told him the court would order him to leave if there was a similar disruption to the one he created Wednesday when he tried to bite off his right little finger immediately after offering "deep apologies to everyone."

The incident prompted the suspension of his first court hearing about 15 minutes into the session. It resumed later in the day without him.

During Friday's session, prosecutors explained to lay judges the victims' wounds and causes of deaths, while presenting images of the attack site.

Uematsu's mental competency is the focus of his trial, with the defense saying he was suffering a mental disorder triggered by marijuana use at the time of the attack. The prosecutors argue that while he holds unusual views, he is fully responsible for his actions.

According to the indictment, Uematsu, a former employee of the care home, stabbed 19 people to death and injured 24 others at Tsukui Yamayuri En in Sagamihara, Kanagawa Prefecture, in the early hours of July 26, 2016.

He is also accused of injuring two employees of the facility by binding them to handrails in a corridor of the building.

The prosecutors said during Wednesday's session that Uematsu started to think after working at the facility that residents of the care home created misfortune for those around them and that it was better to kill people with disabilities.

Last month, Uematsu said in an interview with Kyodo News he continues to believe that "those who have disabilities, severe enough to prevent communication, are not people."

He was diagnosed with narcissistic personality disorder through a forensic mental health assessment during the investigation, leading the prosecutors to judge he can be fully held criminally responsible.

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