U.S. investigators remain stymied after more than a year of investigating as to how some of the most sensitive hacking tools developed by the National Security Agency (NSA) fell into the hands of hackers, The New York Times reports.

The hunt for the mole, moles, or leaks has reportedly caused a major drop in morale at the agency as employees are subjected to intense security checks. These checks include polygraph tests, turning over their passports, and other scrutiny detracting from day to day jobs.

Intelligence officials characterized the leak of hacking tools as far outstripping any damage done by 2013 leaker Edward Snowden. The leaked information has slowly been posted online by a hacking group known as “The Shadow Brokers” purportedly selling the information. Some officials feared the Russian government may be behind the group.

The leaks appear to come from different parts of the NSA raising the possibility of multiple vulnerabilities. Much of the information appears to come from within the agency around 2013, raising questions as to why it is being released now.

The Russia theory too, however, puzzles some experts.

“The problem with the Russia theory is, why? These leaked tools are much more valuable if kept secret. Russia could use the knowledge to detect NSA hacking in its own country and to attack other countries. By publishing the tools, the Shadow Brokers are signaling that they don’t care if the U.S. knows the tools were stolen,” cybersecurity expert Bruce Schneier noted in The Atlantic in March 2017.

“We don’t know what else [they] may have, and most important, we don’t know how this information got out of the National Security Agency, and that’s 15 months after the first leak occurred,” former CIA Director Mike Morell told CBSNews Monday, adding ominously “we don’t know if they’re stealing information as we sit here right now…essentially, the technology we developed at Fort Meade is being used to hack into our governments and companies and some of our personal information.”

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