American personnel on the ground in Benghazi the night of the 2012 terror attack are outraged after learning that the CIA's inspector general never conducted an investigation into what happened -- despite two CIA workers being killed in the attack and despite at least two complaints being filed by CIA employees.
Former Ambassador Chris Stevens, another State official and two ex-Navy SEALs working for the CIA were killed in that attack.
Many in the agency were told, or were under the impression, that an investigation was in the works, but that is not the case.
One person close to the issue told Fox News: "They should be doing an investigation to see what the chief of base in Benghazi and station chief in Tripoli did that night. If they did, they'd find out there were some major mistakes."
This source claimed an investigation would likely uncover a lot of details the public does not know.
Asked why such a probe has not been launched, a CIA spokesman said: "CIA's Office of the Inspector General (OIG) always reviews carefully every matter that is brought to its attention, and takes appropriate action based on a variety of factors."
Still, at least two complaints were filed by CIA employees concerned about the attack, which began at the U.S. compound and eventually spread to the CIA annex one mile away. There is no question that CIA personnel saved a lot of lives; those on the ground that night continue to herald the heroism of the individuals who responded to try and help Stevens and others under attack.
Yet questions remain about the overall decision-making, possible destruction of evidence and warnings of an impending attack.
"There needs to be a CIA investigation ... there was a lot of things done wrong," one special operator said.
But a CIA spokesman said the OIG has already "explained fully" to the agency's congressional oversight committees "why it did not open an investigation into Benghazi-related issues."
"That decision was based on a determination that the concerns raised fell under the purview of the State Department's Accountability Review Board, and that a separate OIG action could unnecessarily disrupt the FBI's criminal investigation into the Benghazi attacks," the spokesman said.
The Accountability Review Board probe was ordered by the State Department, and the board reported its findings in December 2012.
But separate investigations haven't stopped the OIG from investigating issues before. Why they held back in this instance is a question starting to filter through the agents at the CIA. Fox News has been told some of the investigators initially assigned to review the Benghazi complaints are "very upset and very frustrated" that they were told to stop the process.
Some members of the Senate Intelligence Committee expressed some of these same concerns in their review of the Benghazi attacks. On page 15 of the Republican response on Jan. 15, it states: "... the committee has learned that the CIA Inspector General did not investigate complaints relating to the Benghazi attacks from CIA whistle blowers. Whether these complaints are ultimately substantiated or dismissed is irrelevant. On a matter of this magnitude involving the deaths of four Americans, the Inspector General has a singular obligation to take seriously and fully investigate any allegation of wrongdoing. His failure to do so raises significant questions that we believe the Committee must explore more fully."
Fox News has also learned that the Senate Committee was told by the CIA that the investigation did not take place because it would interfere with the State Department Accountability Review Board, which was conducted to "examine the facts and circumstances of the attacks." While that review contained major criticism aimed at State Department officials in Washington, it didn't directly mention the CIA.
"Since when does the CIA defer to State? The ARB is in a total different agency anyway," one special operator said.
Former U.S. United Nations spokesman Richard Grenell also is critical of the CIA actions. "It's puzzling that the Obama administration is so reluctant to do a real investigation of the facts surrounding the Benghazi attack," he said. "The ARB conveniently never interviewed Hillary Clinton or her political team about what they knew in the lead up or how they reacted during the crisis. And now we learn that the CIA wasn't interested in conducting a real investigation either."
The frustration within the agency is building over the fact that many see the CIA inspector general as their last line of defense internally. While the internal complaints are classified, Fox News has learned that besides questioning the actions of the station chief and chief of base, the complaints also question dealings with the Libyan security forces -- and include questions about the reliance on a group of local volunteer militiamen called the February 17 Martyrs Brigade for security and their likely participation in the attack.