We are at a loss for words about the cruelty of the stabbing spree that left 19 dead and 26 injured at a care facility for people with disabilities in Sagamihara, Kanagawa Prefecture, early Tuesday. The motives of the 26-year-old suspect will need to be examined in subsequent investigations. But no rationale can possibly justify this despicable act against utterly defenseless people.

The mass killing — one of the worst in Japan's modern history in terms of the number of victims — will raise questions over security at the Sagamihara center and similar facilities. But there will be limitations to beefing up security systems at such places, many of which suffer from chronic manpower shortages. The suspect, Satoshi Uematsu, worked for more than three years until February at Tsukui Yamayuri En, the site of the carnage, and may have been familiar with the security system there and knew how to get around it.

What must be closely examined is whether the authorities had taken proper actions that could have prevented the carnage — given that the suspect had been making remarks months earlier to colleagues, local officials and police hinting that he planned to kill people with disabilities, and even singled out the Sagamihara home as his "target" in a letter he tried to deliver to the speaker of the Lower House in February.