Dozens of CIA agents were on the ground the night of the Benghazi terrorist attack Sept. 11, 2012, CNN reported Thursday on The Lead, and the agency is involved in what one source calls an "unprecedented attempt" to keep its secrets from ever leaking out.
Agents have been subjected to frequent, sometimes monthly polygraph tests, in order to find out if anyone is talking to the media or Congress, according to sources with insider knowledge of the CIA's workings.
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"It's 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," correspondent Drew Griffin said.
In exclusive communications obtained by CNN, one insider wrote, "You have no idea the amount of pressure being brought to bear on anyone with knowledge of this operation."
CNN reported 35 Americans, with as many as seven wounded, were on the ground that night, although how many were CIA is not known.
Rep. Frank Wolf (R., Va.), whose district include the agency's headquarters in Langley, said he felt the CIA's behavior was a form of cover-up, and the people on the scene should be allowed to testify and reveal what really happened.
Eight Republicans from the Senate and the House this week sent a letter to the new head of the FBI, James Comey, asking he brief Congress within 30 days, but no Democrats signed on.
In the aftermath of the attack, Wolf said he was contacted by people with close ties to CIA operatives and contractors who wanted to talk, but suddenly there was silence.
"Initially, they were not afraid to come forward," Wolf said. "They wanted the opportunity and they wanted to be subpoenaed, because if you're subpoenaed it sort of protects you. You are forced to come before Congress. Now that's all changed."
CNN reported Wednesday it had scored a two-hour interview with a lead suspect in the Benghazi attack, Ahmed Abu Khattala, the Benghazi leader of the al Qaeda-affiliated militia group Ansar al-Sharia, and he had not been contacted by the FBI or Libyan officials.
The CIA, in an official statement, asserted it's being open with Congress on Benghazi.