Prosecutors in Germany have seized 10 servers which hosted the anonymising service TOR.
The action has raised fears of a wider clampdown against the service, which provides a way for people to browse the internet anonymously. The seized machines are assumed to be TOR exit nodes.
But according to at least one blogger, the police seized the machines as part of a child porn investigation.
It seems the IP numbers of the machines were found during an investigation into a chatroom where images were being traded.
One of the volunteers who run the servers, and had his machine seized, told a newsgroup that prosecutors told him he was allowed to run TOR in Germany. The prosecutor apparently asked the administrator whether it was possible that the machine had been hacked.
None of the administrators has been told whether or not they will face criminal charges.
The action has raised obvious fears from other volunteers running TOR servers. The service works by sending information requests through a network of machines called onion routers.
It has been used by many groups and organisations including, at one time, parts of the US Navy.