In what current and former FBI agents say was a highly unusual move, agents working the Clinton email case had to sign a separate non-disclosure agreement to work on the case.

In fact, one former agent said he had "never heard" of such a thing and had never had to circulate the "Case Briefing Acknowledgment" form in his entire career.

New York Post:

Sources said they had never heard of the “Case Briefing Acknowledgment” form being used before, although all agents must initially sign nondisclosure agreements to obtain security clearance.

“This is very, very unusual. I’ve never signed one, never circulated one to others,” said one retired FBI chief.

An FBI agent currently on the job admitted, “I have never heard of such a form. Sounds strange.”

Meanwhile, FBI agents expressed their “disappointment” over FBI Director James Comey’sdecision not to recommend charges against Clinton, sources close to the matter told The Post.

“FBI agents believe there was an inside deal put in place after the Loretta Lynch/Bill Clinton tarmac meeting,” said one source.

Another source from the Justice Department was “furious” with Comey, saying he’s “managed to piss off right and left.”

The NDA is pure politics, as the Justice Department sought to minimize leaks to the press about Hillary's legal problems.  While it's a legitimate question as to whether FBI agents should be talking to the press at all, anyone familiar with Washington knows that's not how the city works.  The government literally runs on gossip, which is why so much business is done at dinner parties and during the cocktail hour.

The Clinton campaign sought to exert ironclad control over the email story from the beginning and were largely successful in doing so.  And they got a big assist from the Obama administration when his Department of Justice gagged FBI agents who might have helped keep the public informed.