Japanese hacker arrested for fishy malware

A Japanese hacker has been arrested on suspicion of creating malware which deletes a user's computer files and replaces them with manga-style images of octopuses and squid.

Up to 50,000 computers may have been infected by Masato Nakatsuji, 27, of Izumisano, Osaka Prefecture, the Asahi Shinbun reported today.

High-tech crime officers said Nakatsuji is suspected of writing the Ikatako (squid-octopus) virus, which was distributed on the Winny file-sharing site in May, disguised as a file for anime songs, according to the report.

He was arrested whilst serving a suspended sentence for a previous offence and reportedly told police: "I wanted to see how much my computer programming skills had improved since the last time I was arrested."

Police arrested Nakatsuji in 2008 for violating copyright laws by writing a virus which replaced user files with anime images.