A man accused of killing 19 residents at a care home for mentally disabled people near Tokyo is expected to plead not guilty at a trial to begin in January, sources familiar with the matter said Friday.

The defense team of Satoshi Uematsu, 29, plans to argue in the trial that he was mentally incompetent due to the effects of drugs such as marijuana, the sources said.

Uematsu is accused of stabbing 19 people to death and injuring 24 others at the care home in Sagamihara, Kanagawa Prefecture, in the early hours of July 26, 2016, as well as hurting two employees of the facility by binding their bodies to handrails in a corridor of the building.

Many of the victims were unable to communicate due to their disabilities.

[Fowers are laid on an altar set up at the facility on July 26, 2019, the third anniversary of the 2016 stabbing rampage]

Prosecutors have contended that Uematsu, a former employee of the care facility, was fully mentally competent to bear responsibility for his acts, although he was diagnosed with a personality disorder associated with narcissism at an early stage of the investigation following his arrest.

Uematsu had previously been diagnosed with mental problems associated with the use of marijuana. He also tested positive for the drug after his arrest.

The trial is scheduled to start on Jan. 8 at the Yokohama District Court and a ruling will be handed down on March 16.

The gruesome incident has sent shockwaves through Japan, with Uematsu continuing to make discriminatory remarks against those with disabilities in written interviews with media, saying people who cannot communicate bring "misfortune."