The three met through online games. According to the MPD's' cybercrime division, the three used the IDs and passwords of 11 Rakuten account holders to illegally access Rakuten Mobile's' servers from May to August 2024 and contracted for 105 mobile phone lines. However, the three had obtained 3.3 billion IDs and passwords for various services. This data was not exclusive to Rakuten. Police said the trio's activities, adding up to their arrest for violating the unauthorized computer access law and committing computer fraud, began in December 2023; this was when they started purchasing IDs and passwords on the highly confidential Telegram communication app. The 16-year-old told investigators he used the generative artificial intelligence platform ChatGPT to create a system to extract and share the Rakuten account data. The 14-year-old is believed to have devised the system, telling investigators, "I wanted t" attract attention by devising a criminal scheme," according"to the MPD.