Kyoto prefectural police have arrested an engineering graduate school student on suspicion of creating and spreading a computer virus via the peer-to-peer, file-sharing software program Winny. He is believed to be the first person in Japan to be arrested in connection with creating a computer virus. The circumstances of his arrest show that Japan is not well prepared legally to fight cybercrime. The lack of laws to punish those who create and use computer viruses forced police to accuse the suspect of violation of the Copyright Law.

He is suspected of having downloaded a still image of a TV animation film, altered it, embedded a computer virus in it and distributed it via the Internet. The virus infects certain programs in personal computers. After the programs are infected, the virus generates another virus that steals document files and Internet protocol addresses and then destroys the data.

In 2001, Japan signed the Council of Europe Convention on Cybercrime. In order to be able to ratify it, the government in 2004 proposed revising the Penal Code to punish those who create and use computer viruses and to enable confiscation of electronic storage mediums as evidence. Since the revision is paired with another revision to the Penal Code, which would introduce the "crime of conspiracy," the revision bill has been dormant in the Diet. The introduction of the crime of conspiracy has met strong opposition because the crux of the proposal is that one would be punished for joining others in planning a crime even if the crime was not actually committed or concrete preparations were not made to commit it. Japan must introduce the crime of conspiracy to ratify the 2000 United Nations Convention Against Transnational Organized Crime.