The CIA has been subjecting operatives to monthly polygraph tests in an attempt to suppress details of a reported US arms smuggling operation in Benghazi that was ongoing when its ambassador was killed by a mob in the city last year, according to reports. Up to 35 CIA operatives were working in the city during the attack last September on the US consulate that resulted in the death of Ambassador Chris Stevens and three other Americans, according to CNN. The television network said that a CIA team was working in an annex near the consulate on a project to supply missiles from Libyan armouries to Syrian rebels. Sources said that more Americans were hurt in the assault ... than had been previously reported. CIA chiefs were actively working to ensure the real nature of its operations in the city did not get out. So only the losses suffered by the State Department in the city had been reported to Congress. Frank Wolf, a US congressman who represents the district that contains CIA headquarters in Langley, Virginia, is one of 150 members of Congress for a new investigation into the failures in Benghazi. I think it is a form of a cover-up, and I think it's an attempt to push it under the rug," he said. "We should have the people who were on the scene come in, testify under oath, do it publicly, and lay it out. And there really isn't any national security issue involved with regards to that."