In the early dawn of July 26, 2016, a man with knives broke into and carried out an assault on a care home for people with disabilities in the south of the Tokyo Metropolitan Area, Japan. The man, Satoshi Uematsu, and a former employee of the care home threatened staff members during their night shift, bound them with zip ties, and deprived them of their mobility.

Uematsu started to wake up inmates one by one, checked the degrees of their disability, selected inmates whom he regarded as severely disabled, and stabbed or slashed them on their beds. Eventually, 19 inmates were killed, and 24 others were injured. After fleeing the care home, he turned himself into the police.

The event sent a shockwave throughout Japan and even overseas. As for his motive, Uematsu maintained people with severe disabilities should be put under euthanasia. There seems to be no evidence that clearly indicates Uematsu, in developing his own extreme view, absorbed specific ideology or the like in a systematic manner, and it is concluded he developed the view mostly on his own.

Uematsu’s assault on a care home is not generally seen as politically or ideologically motivated, but his attempt to add theory to his view makes the case more ominous. Though such a theory looks obviously irrational to anybody’s eyes, it can be enough to give his case more transmissible power in igniting a copycat.