The man accused of hacking other people’s computers to make a series of violent threats in 2012 maintained his “absolute innocence” as his trial opened Wednesday at the Tokyo District Court.

Yusuke Katayama, a former employee of a Tokyo information technology company, was arrested in February 2013 on suspicion of remotely manipulating other people’s computers to threaten violence, including mass murder, causing severe business obstructions.

The threats included killing kindergartners and “otaku” participants in an amateur manga market event. In one instance, Katayama allegedly announced he would bomb a New York-bound Japan Airlines jet, prompting the carrier to halt a flight halfway, costing JAL ¥9.75 million.

As he entered the courtroom, Katayama, in a black suit, grinned at the gallery. With a confident, sonorous voice, he said the allegations are “complete nonsense” and pleaded not guilty to all 10 counts against him.

Prosecutors say Katayama used popular online forums such as 2channel to disperse a virus called iesys.exe so he could infiltrate other people’s computers and control them by stealth.

The threats that came from these compromised computers, made from June to September 2012, resulted in four wrongful arrests, in Tokyo and Osaka, Fukuoka and Mie prefectures.

All of the people falsely arrested initially denied wrongdoing, but two of them eventually admitted guilt, spurring concerns that prosecutors coerced them into confessing. They were all released in October 2012 when a person claiming to be the real culprit sent email to authorities containing details that had not been made public.

The case took another bizarre turn in January 2013 when someone sent a provocative email to many journalists and authorities, daring them to solve a series of attached “riddles” that tested their technological prowess.

The riddles ultimately led them to a cat on the island of Enoshima in Kanagawa Prefecture. Tied up to its collar was a small computer chip micro SD digital storage card with a message suggesting the culprit held a grudge against authorities for having once implicated him in a crime “despite my innocence.”

Katayama was arrested in 2005 for posting an online death threat against employees of the Avex Inc. music label and served 18 months behind bars. He stressed Wednesday that he is truly sorry for what he did and “my current criticism of the police and prosecutors has nothing to do with the way they treated me back then.”

He complained that he has been kept detained incommunicado for about a year and that his repeated calls for bail have fallen on deaf ears. He said he has been denied any visitors, including his ailing mother, with whom he lived.

Prosecutors claimed they found a string of characters on Katayama’s office computer that imply he developed, revised and compiled the virus, and that the computer also contained a trial version.

They said Katayama’s mobile phone records show that he had looked up such keywords as”cat” and “Enoshima” before the cat riddle incident became known to the public.

His lawyers argued that Katayama’s computer could have been infected with the virus and remotely controlled by the true culprit. The culprit must have hacked Katayama’s computer, found he had looked up those words and decided to make a scapegoat of him by devising the Enoshima riddle, they said.

Security camera footage from the island shows Katayama playing with the cat in question, but he denies tampering with its collar.

Katayama also claimed his knowledge of programming, despite his experience in the IT industry, is not sufficient to develop such a highly intricate virus.

His lead lawyer, Hiroshi Sato, on Monday slammed Katayama’s arrest and detention as a result of the authorities’ failure to “learn their lesson from the preceding wrongful arrests they made.”

While the prosecutors intend to prove Katayama guilty by presenting as many as 637 pieces of circumstantial evidence, none of them, according to Sato, is decisive, and “no amount of these would even come close to incriminating him.”

In a time of both misinformation and too much information, quality journalism is more crucial than ever.
By subscribing, you can help us get the story right.