Tokyo police have arrested three teenage boys on suspicion of fraudulently subscribing to Rakuten Mobile's phone service via a self-made program using artificial intelligence.

The Metropolitan Police Department's cybercrime unit believes that the boys obtained at least about 2,500 mobile phone subscriptions in about six months from December 2023 and sold them for a total of about ¥7.5 million in crypto assets.

The arrests were made for allegedly obtaining 105 mobile phone subscriptions between May and August last year by logging into the Rakuten Mobile system with other people's IDs and passwords.

The boys — a 14-year-old third-year junior high school student in Tokyo, a 16-year-old first-year high school student in Gifu Prefecture and a 15-year-old third-year junior high school student in Shiga Prefecture — have admitted to the allegations, according to police sources.

One of the three was quoted as saying that he wanted to attract attention on social media by devising and carrying out a sophisticated criminal scheme.

According to the sources, the high school student led the development of the program, which automatically logged into the Rakuten Mobile system and subscribed to its mobile phone service. The program used ChatGPT, an interactive generative AI tool.

The students allegedly used IDs and passwords they purchased from someone they met on Telegram, a highly confidential messaging app. About 3.3 billion sets of IDs and passwords were found in the students' personal computers.

The students sold Rakuten Mobile subscriptions to several people for crypto assets, and used the assets to play at online casinos and buy game consoles, the sources said.

Police also discovered about 10,000 sets of credit card information in the students' personal computers and are investigating whether they used the information illegally.