On March 18, 2011, Sidney Blumenthal -- Clinton's longtime friend and political adviser -- sent the then secretary of state an email to her private account that contained apparently highly sensitive information he had received from Tyler Drumheller, a former top CIA official with whom Blumenthal at the time had a business relationship.
"Tyler spoke to a colleague currently at CIA, who told him the agency had been dependent for intelligence from [redacted due to sources and methods]," the email states, according to Gowdy's letter.
The redacted information was "the name of a human source," Gowdy wrote to his Democratic counterpart, Rep. Elijah Cummings (D-MD) of Maryland, and was therefore "some of the most protected information in our intelligence community."
"Armed with that information, Secretary Clinton forwarded the email to a colleague -- debunking her claim that she never sent any classified information from her private email address," wrote Gowdy in a letter to Cummings.