Servers seized by the FBI from the alternative media network known as Indymedia have been returned.
Italian police are investigating Indymedia
The servers in the outskirts of London were taken last week by the FBI which said it was acting on behalf of Italian and Swiss authorities.
Indymedia hosts sites, news and radio feeds for anti-globalisation groups and other campaigners for social justice.
The media group is now taking legal advice about what action it can take over the seizure of its hardware.
During the 7 October raid hard drives were taken that held the websites for many local Indymedia groups, audio feeds for net radio stations as well as several other groups.
Indymedia said some of the 20 sites knocked out by the raid were restored from back-up copies soon after the originals were taken.
Others, such as Antwerp, Belgrade, Liege and Lille, took longer to restore.
Indymedia said some of its local affiliates, notably Uruguay, Italy, Western Massachusetts and Nantes, lost data because of the seizure.
The media group said it had verified that the hard drives returned on 13 October were the ones actually taken in the raid.
With the help of the cyber-liberties group the Electronic Frontier Foundation, it is making sure the returned data is secure and has taken its own copy of it in case of future legal action.
"EFF is deeply concerned about the grave implications of this seizure for free speech and privacy," said Kurt Opsahl, staff attorney for the EFF.
"We are exploring all avenues to hold the government accountable for this improper and unconstitutional silencing of independent media," he said.
The raid was also condemned by the International Federation of Journalists which called it an: ""unacceptable and intrusive international police action".
The drives were seized from the London offices of a San Antonio-based company called Rackspace that hosts the Indymedia sites.
Rackspace said the legal justification for the raid included a gagging order that prevented it revealing details.
The returned drives are being examined
The servers were apparently seized under the Mutual Legal Assistance Treaty which is typically used by nations co-operating to investigate cross-border crimes such as terrorism, kidnapping and money laundering.
In a statement posted on its main website Indymedia said evidence was emerging that four different countries, the US, UK, Italy and Switzerland, were behind the server seizure.
Italian authorities were reportedly investigating the Italian Indymedia group for "supporting terrorism".
Swiss authorities said the raid could help its investigation of Indymedia coverage of 2003's G8 Summit in Evian.