CNN has uncovered exclusive new information about what is allegedly happening at the CIA, in the wake of the deadly Benghazi terror attack. Four Americans, including Ambassador Christopher Stevens, were killed in the assault by armed militants last September 11 in eastern Libya.

Sources now tell CNN dozens of people working for the CIA were on the ground that night, and that the agency is going to great lengths to make sure whatever it was doing, remains a secret.

CNN has learned the CIA is involved in what one source calls an unprecedented attempt to keep the spy agency’s Benghazi secrets from ever leaking out.

Since January, some CIA operatives involved in the agency’s missions in Libya, have been subjected to frequent, even monthly polygraph examinations, according to a source with deep inside knowledge of the agency’s workings.

The goal of the questioning, according to sources, is to find out if anyone is talking to the media or Congress.

It is being described as pure intimidation, with the threat that any unauthorized CIA employee who leaks information could face the end of his or her career.

In exclusive communications obtained by CNN, one insider writes, “You don’t jeopardize yourself, you jeopardize your family as well.”

Another says, “You have no idea the amount of pressure being brought to bear on anyone with knowledge of this operation.”