The FBI agent who first brought the case of David Petraeus' affair to the bureau has been identified as Frederick Humphries, CBS News reported Wednesday night.

As a friend of wealthy Tampa, Fla., party hostess Jill Kelley, Humphries took her concerns about harassing emails to the FBI's cyber squad in Tampa, CBS News reports. That investigation eventually led to the discovery of the Paula Broadwell-David Petraeus affair and the retired general's sudden resignation as CIA director.

Law enforcement sources tell CBS Humphries became disgruntled with being cut out of the investigation and he eventually leaked information to members of Congress.

On Tuesday, Kelley's pass to enter MacDill Air Force Base in Tampa, home to the U.S. Central Command, was revoked because of the investigation, USA Today reported. Called a "Friends of MacDill" pass that allows easier access to the base, the first one was issued to Kelley in November 2010 after she submitted information, including her Social Security number, for a background check.

Kelley was known for her parties for members of the military in Tampa. But unless you held the rank of general or admiral, you weren't likely on the guest list, according to one retired senior officer who didn't want his name published.

"A colonel is about as low as she'd go," the officer, who served at Centcom, told USA Today.

Kelley has done fundraising for the U.S. military, and Humphries is a veteran counter-terrorism agent, but the details of their relationship are unclear. The FBI soon traced the emails to Broadwell, a former Army intelligence officer and author of "All In: The Education of General David Petraeus."

The FBI investigation uncovered about a half-dozen emails from Broadwell to Kelley. While they did not openly name Petraeus, some of them contained information about his travel schedule -- details not usually available to the public.

Humphries later contacted Rep. Dave Reichert, R-Wash., who then relayed the information to House Majority Leader Eric Cantor, R-Va., raising concerns of a national security risk. But the leaders of the congressional intelligence committees were kept in the dark until the scandal broke Friday.

Humphries has since been reassigned, and his status is under review by the FBI. Humphries is the agent who once sent a shirtless picture of himself to Kelley, but it happened a long time ago, well before the investigation, CBS said.

Lawrence Berger, the general counsel for the Federal Law Enforcement Officers Association, said in an interview with the New York Times that his client, Humphries, did nothing wrong and should not be disciplined. “He’s committed no misconduct,” Berger said, and he predicted he would be cleared of any misconduct.

Kelley met Humphries when she attended the Citizens’ Academy, an FBI public relations program, Berger said.

The shirtless photo was part of a joke that has been taken out of context, according to Berger.

“That picture was sent years before Ms. Kelley contacted him about this, and it was sent as part of a larger context of what I would call social relations in which the families would exchange numerous photos of each other,” he told the Times.

Petraeus is to appear before the Senate Intelligence Committee Thursday in a closed hearing on the Sept. 11 terror attack in Benghazi, Libya.