State police in Munich are investigating whether file-swapping platforms like Napster and Gnutella are being used to trade child pornography and whether users have stored illegal material on their PCs.

"We are conducting inquiries in connection with that," said spokesman Fritz Dillinger of the Landeskriminalamt Bayern (Bavarian State Criminal Office). He said he could offer no further details.

The German online publication "Computer Channel" reported on Tuesday that its searches of the file exchanges revealed, in addition to music files, large amounts of pornographic material and pirated software packages were available for download from users' hard drives on these sites.

The article added that Napster no longer enables downloading of material other than compressed audio files in the MP3 (MPEG Audio Layer 3) format, though its search engine still turns up such files.

Competing services like the loosely-organised Gnutella network and Linux Music LLC's MyNapster still make possible such downloads, however.

Napster and Linux Music could not be immediately reached for comment.