The alleged cyberriddler accused of issuing online threats that triggered four false arrests last year was indicted Friday afternoon over a bomb threat sent to Japan Airlines from a hijacked computer in Osaka Prefecture, prosecutors said.
The Tokyo District Public Prosecutor’s Office charged Yusuke Katayama, 30, with violating the hijack prevention law and other legislation, they said.
Katayama, an information technology employee, was arrested in February on suspicion of sending an email to JAL last August, threatening to blow up a JAL flight, and of posting a threat of mass murder on the website of the Osaka Municipal Government in July. Both messages were sent from the hijacked PC of a man in Osaka.
Tokyo prosecutors also indicted Katayama for obstruction of business in a separate case in which a mass murder threat was sent from a hijacked PC at a company in Aichi Prefecture.
Katayama has consistently denied his involvement in the threats. He was arrested after being sited on a surveillance camera on Enoshima approaching a cat that was later found with a memory chip on its collar containing the computer virus used to post the threats. The cat was tracked down by solving a riddle allegedly sent to media organizations by the cyberriddler.
According to the prosecutors, the virus that infected the Osaka man’s PC was stored on a server in the United States. Japanese investigators analyzed the server in cooperation with the FBI and found data showing that the virus had been made on and sent from a PC Katayama used at a company he had been dispatched to, the sources said.
Since the PC was managed by Katayama through his identification code and password, authorities believe he was the one who made and sent the virus.
The man who owned the computer in Osaka was indicted by the Osaka District Public Prosecutor’s Office last September for obstruction of business pertaining to the mass murder threat. It dropped the charges the following month after discovering the virus.
A joint investigation team including the Metropolitan Police Department believes Katayama used a virus to remotely control the PCs of other people in two more threat cases that fooled police into making false arrests.
The cases involved two men, one in the city of Fukuoka and the other in Mie Prefecture, who were wrongly arrested.