Tokyo, Nov. 9 (Jiji Press)–Tokyo’s Metropolitan Police Department has arrested an unemployed Chinese man for allegedly operating an unauthorized mobile phone base station in central Tokyo in violation of Japan’s radio law. The suspect, Yu Hai, 31, a resident of Tokyo’s Kita Ward, was arrested at the scene Saturday on suspicion of operating a radio station without a license using a transmitter installed in a vehicle in the Japanese capital’s Ginza district. The man has denied the allegations, saying that he had never used a radio transmitter, according to investigative sources. On Monday, the MPD also referred the man to prosecutors on suspicion of violating the same law by interfering with Japanese mobile phone carrier NTT Docomo’s services. It is believed to be the first such case nationwide involving interference with mobile phone communications. According to the MPD and other sources, the suspect used specialized equipment installed in the car to transmit jamming signals that cut off normal communications, forcing handsets to connect to the fake base station, which transmitted signals using the older 2G (second-generation) standard. The 2G standard has a weaker authentication system than 4G and 5G, and the suspect is believed to have exploited this vulnerability to send fraudulent messages in Chinese through the short message service. The messages reportedly said that credit card payments had been temporarily suspended due to the risk of unauthorized use overseas, and directed recipients to websites where they were prompted to enter their card information and other details. The suspect is believed to have repeated such activities in Ginza as well as Shinjuku and Shibuya wards in the capital. Around 10,000 smartphones were reportedly left without mobile phone service each day within a radius of at least 500 meters, due to the jamming. Since January last year, 18 people, including Chinese tourists, have contacted the MPD about the incidents, with total losses estimated at around 4 million yen. The MPD is investigating whether the operation involved an organized group. In December 2024, NTT Docomo received reports of communication disruptions from users and identified the suspect during an investigation the following month. The communications ministry issued verbal guidance after receiving a report from the company, but the suspect continued to carry out similar activities. In May last year, the ministry issued a warning that interference with mobile phone services had occurred due to radio equipment suspected of being operated illegally. END [Copyright The Jiji Press, Ltd.]
