Satoshi Uematsu, the suspect in last week's murder spree at a care facility for people with disabilities in Sagamihara, Kanagawa Prefecture, had abused quasi-legal drugs and made radical remarks for years before the massacre, friends and acquaintances say.

They started noticing his odd behavior around summer 2013, when the remarks began to isolate him from his friends.

While at a barbecue, for example, he asserted that he could see a runway in the mountains, plus other remarks that didn't make sense, apparently influenced by the hallucinogenic compounds now called kiken (dangerous) drugs.