A man accused of killing 19 residents at a care home for people with mental disabilities in Kanagawa Prefecture is expected to plead not guilty at a trial set to begin in January, sources familiar with the matter have said.

The defense team for 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 Friday.

Uematsu is accused of stabbing 19 people to death and injuring 26 others at Tsukui Yamayuri En in Sagamihara, Kanagawa Prefecture, in the early hours of July 26, 2016. The injured included two employees who had their bodies bound to handrails in a corridor of the building.