What is important for the virus writer was that he (or maybe she) sent announcement emails to the mass media, claiming that the Japanese police were incompetent and couldn't tackle with cyber-crime. Also, the perpetrator even sent a puzzle to the police, saying that if the police could solve it, they would get a clue of the suspect. The police solved the puzzle and went to the designated place where they found a cat with a choker ring on which an SD card was attached. These scenes have been broadcasted by the media again and again and the Japanese people were horrified by the unknown and terrible computer virus.
On February 10, the police announced that they had arrested a 30 year old man in Tokyo as the suspect of the cyber-crime. According to the media, the clue was on the SD card. The message on the card said: "My life was ruined by the false charge." The police claims that the arrested person had actually been convicted of sending a threatening message regarding the conflict between the users of a bulletin board, called "2ch", and Japanese major record company, Avex, about unlicensed usage by Avex of a character loved by 2ch users called "Mona."
As the arrested seems to be claiming his innocence, it is not clear at this stage whether he is the real cyber-criminal. However, what I found most important regarding this case is that the Japanese police forced many people to make false confessions during the interview. Most of the arrested framed by the virus writer eventually "confessed" to sending threatening emails. However, this was not true. The reason they confessed was because of the police's strong pressure during the interview. Although I admit the unique nature of Japanese criminal law which makes confessions important (such as the emphasis on the state of a criminal's mind), I think that the lesson of this case for the police is to reflect on themselves and refrain from applying too much pressure during an interview.