The Electronic Frontier Foundation (EFF) has filed a lawsuit against the US Department of Justice (DOJ) seeking information about a huge database containing the personal information of potentially millions of people.

The EFF, a civil liberties and privacy advocacy group, has asked the US District Court for the District of Columbia to force the DOJ to release details about how it collects information and how it decides whose information to include in the Investigative Data Warehouse (IDW), operated by the DOJ's Federal Bureau of Investigation (FBI). The EFF filed the lawsuit Tuesday.

The database was designed to include information such as photographs, biographical information, physical location and financial data for use in antiterrorism investigations, according to information from the FBI. Earlier this year, FBI officials said there were more than 560 million documents in the database, and about 12,000 law enforcement agents had access to the information.

In March 2005, an FBI official described the database as containing just 100 million documents, according to the EFF complaint. The database "appears to be growing at a tremendous rate," the EFF said in its court filing.

An FBI spokesman did not immediately respond to a request for comment on the EFF lawsuit.

The EFF has filed two Freedom of Information Act (FOIA) requests with the FBI since late August, asking for information about the criteria for inclusion in the database and the agency's privacy policy to protect what the EFF called "sensitive information" in the database.

The FBI failed to file a public notice describing the database and the criteria for including personal information, as required by the Privacy Act of 1974, the EFF said. Without a public notice, people whose information is in the database have no way to correct inaccurate data, said David Sobel, a senior counsel at the EFF.

Because the FBI has been largely silent about the database, it's unclear if its database contains information mostly focused on US residents or people from other countries, Sobel said. "There are a lot of interesting questions that a database of this size raises," he added. "The FBI hasn't been inclined to answer many of them."

The EFF is not asking the court to order the release of information held in the database, Sobel said. "We're not asking for the disclosure of anything that ought to be that sensitive," he said.