Allegedly, the teenager is a self-styled hacker who illegally accessed another individual's online game server and also wrote three gamers' IDs and passwords on an internet forum. For that, Japanese police arrested him.
The recent crackdown comes as the country's law was revised to make it illegal to post people's IDs and passwords online without permission.
他人のＩＤなど公開の１６歳逮捕…提供罪初適用 [Yahoo! Japan]