According to an NBC News report, an "overwhelmed" National Security Agency still isn't sure which files Edward Snowden took with him when he fled to Hong Kong more than two months ago.

Citing two separate sources briefed on the matter, NBC News reports that the remaining unreleased documents likely include information about the intelligence gathering techniques of the U.S.'s key allies, including United Kingdom, Canada, Australia, and New Zealand.

If true, that might explain the recent U.K.-led crackdown on journalists and (their partners) who have had access to Snowden's leaked documents. On Sunday, David Miranda, the partner of Guardian journalist Glenn Greenwald—the first to break the Snowden story—was detained for nine hours in London's Heathrow Airport under the rarely used “Schedule 7 of the Terrorism Act of 2000”; all of Miranda's electronic equipment, including a laptop and flash drives, were confiscated. And last month, Guardian employees, under pressure from U.K. government officials, destroyed various hard drives and memory cards that once held the files leaked by Snowden.

[Image via AP]