A 20 year-old German man has turned himself over to the police for owning child pornography after an email worm warned that he was being 'investigated'.

The man had received a copy of a mass email that was sent by the Sober Y internet worm. 

The worm spreads using several email messages, one of which has a subject line in German that states: 'Preliminary investigation commenced'. The body of the message reads:

'The downloading of movies, software and mp3s is illegal and therefore punishable. We can hereby inform you that your computer and IP address have been confiscated.

'The contents of your computer have been seized as evidence and a preliminary investigation will be launched. In the coming days, you will receive a written statement informing you of the charges and your options to file a statement.'

The email is signed by the German Federal Bureau of Criminal Investigations and comes with an attachment containing the Sober Y virus.

The message prompted the man to turn himself in at a police station in the city of Paderborn, a local police press release claimed, confessing that he owned pornographic pictures of children. 

An investigation showed that the man had sent images by email and stored images on his hard drive. Police have launched a criminal investigation, but said that the man is not an active member of any crime ring producing child pornography.

"Email worms are not always as harmful as generally thought," the police bulletin concluded.