Suspect in online threats may have used PCs at client firm


A man arrested Sunday in connection with online murder and other threats that were remotely routed through innocent people’s computers may have originated the messages from PCs at a company where he had been dispatched by his employer.

The threats led to four people being arrested by mistake.

A joint investigation team, including Metropolitan Police Department officers, seized PCs and other equipment from the company in Minato Ward, Tokyo, sources said Monday.

The suspect, Yusuke Katayama, who has been employed by an information technology firm in Shinagawa Ward since 2008, was dispatched to the Minato Ward company as a computer programmer, the sources said without naming the companies.

Katayama, a Tokyo resident, was arrested Sunday for posting a message with a threat to commit mass murder at a manga event in Tokyo. The message was posted on an Internet forum last Aug. 9 using a remotely controlled virus-infected PC belonging to a firm in Nagoya.

The police turned Katayama, 30, over to prosecutors Monday.

Last year, police arrested four people after online murder and assault threats were sent from their PCs. But the four were later freed and given apologies after it was determined their PCs were infected with a remotely controlled virus that sent out the threats without their knowledge. The police now suspect Katayama was behind all of those cases.

According to the sources, the PCs seized from the Minato Ward company contained tell-tale signs indicating that Tor software, which enables online anonymity, was used many times.

Tor software was used when the online threats were posted in the wrongful arrest cases. Police have also confiscated PCs from Katayama’s home.