Second Life is being investigated by German police following allegations that some members are trading child pornography in the online world.
The investigation follows a report by a German TV news programme which uncovered the trading group and members who pay for sex with virtual children.
The police are now trying to identify the Second Life members involved.
Linden Lab, the creator of Second Life, said it would help identify users and pass on details to prosecutors.
Second Life, as its name implies, is a virtual world in which members create an avatar and then use that character to live out a separate existence.