She was among five girls in Japan believed to have beaten a boy so severely that he required hospital treatment. Yet her most pressing concern was how much money the group should demand from him. To find an answer, she turned to artificial intelligence. The alleged assault took place in January in Hachioji, a city in western Greater Tokyo. For experts, the case has exposed a disturbing pattern: Japanese adolescents instinctively turning to AI to guide their actions, including criminal ones,...