The Justice Department is blocking the release of files from United Against Nuclear Iran, after the groups donor lists and other documents were requested in a defamation lawsuit, according to Matt Apuzzo at The New York Times. As Apuzzo notes, the government's involvement raises questions about how the two are connected.

U.A.N.I., an organization staffed and advised by a bi-partisan coalition of former government officials, lobbies Congress and helps draft legislation. But it's best known for publicly shaming businesses that violate sanctions and work with Iran. (In 2009, the group pressured the InterContinental Barclay Hotel in New York against housing the previous president of Iran, Mahmoud Ahmadinejad.)

Last year the group accused Victor Restis, a Greek businessman and owners of one of the country's biggest commercial fleets, of being a frontman for "the illicit activities of the Iranian regime," and using his ships for Iranian oil business according to The Times. Restis responded by arguing the group is backed by foreign interests, and demanded that the donor list be made public.

That's where the government stepped in. Justice Department officials argued that release the documents would reveal investigation techniques, compromise current investigations and/or reveal sources. It's not clear whether U.A.N.I. gained unauthorized access to government files, or why they files are sensitive, but as Apuzzo notes, the fed's involvement has "lent credibility to the idea that larger, hidden interests were at stake." The Justice Department has until Thursday to decide if it will try to keep the files secret permanently.