No one knows for sure, but the appearance of what had been a highly-classified court decision has some wondering if the FISA court has sprung its first significant leak.  The Daily Beast’s Eli Lake reports that the FBI has begun to wonder that, too — although the list of suspects in this case is long and distinguished:

The FBI is investigating whether the highly protected and segregated computer systems that store the secret court warrants authorizing electronic surveillance inside the United States have been breached, according to current and former U.S. intelligence officials. Thirteen days after the Guardian published a top-secret court order from the top-secret Foreign Intelligence Surveillance Court disclosing the National Security Agency’s collection of all phone records from Verizon’s business customers over a three-month period, the U.S. intelligence community has yet to determine how the warrant, one of the most highly classified documents inside the U.S. government, was leaked.

Those who receive the warrant—the first of its kind to be publicly disclosed—are not allowed “to disclose to any other person” except to carry out its terms or receive legal advice about it, and any person seeing it for those reasons is also legally bound not to disclose the order. The officials say phone companies like Verizon are not allowed to store a digital copy of the warrant, and that the documents are not accessible on most NSA internal classified computer networks or on the Joint Worldwide Intelligence Communications System, the top-secret internet used by the U.S. intelligence community.

The warrants reside on two computer systems affiliated with the Foreign Intelligence Surveillance Court and the National Security Division of the Department of Justice. Both systems are physically separated from other government-wide computer networks and employ sophisticated encryption technology, the officials said. Even lawmakers and staff lawyers on the House and Senate intelligence committees can only view the warrants in the presence of Justice Department attorneys, and are prohibited from taking notes on the documents.

There had been some speculation that Snowden might not be the only source for the scoops by the Guardian and Washington Post.  It’s not even clear that Snowden had access to the FISA warrant.  Capitol Hill says it wasn’t them:

“The only time that our attorneys would have gotten to read one was if Justice Department lawyers came over with it in a secure pouch and sat there with them when they read them,” said Pete Hoekstra, a former Republican chairman and ranking member of the House Permanent Select Committee on Intelligence.  “There was never one in the intelligence committee spaces, never one left there without someone from the Justice Department. It would not have been left there over night.”

That raises other questions, of course.  What else might secret courts do with secret laws, where attorneys representing the accused can’t attend and even the transcripts can’t be seen by Congress without a baby sitter?  There may be an argument for this much secrecy on the most acute counter-terrorism cases, but these applied to the broader collection taking place at the NSA.