Kenichiro Okamoto had just finished giving a seminar on resolving online disputes Sunday night when the well-known Japanese blogger was stabbed to death by a man he'd argued with online, the Guardian reports. Hidemitsu Matsumoto allegedly followed Okamoto into the bathroom at the event venue in Fukuoka and stabbed him multiple times in the chest and neck; Okamoto was able to leave the bathroom, but was pronounced dead at a nearby hospital. Matsumoto escaped the scene on a bicycle, but turned himself in to authorities three hours later.
Okamoto, 41—better known by his screen name, Hagex—had allegedly received abusive messages from Matsumoto, 42, who reportedly admitted to opening a new account every time his was deleted so that he could continue to send messages. He allegedly told police he hated Okamoto, an expert on cybercrime and the dark web who was also regularly seen on TV, and wanted him dead. Citing local reports, the Telegraph says Matsumoto has been described as a "hikikomori," someone who has retreated from society and communicates only online; Newsweek describes him as a troll. He allegedly has a history of cyber disputes. (This app turns the tables on internet trolls.)