The U.S. attorney in Arizona violated Justice Department policy by providing Fox News with information apparently aimed at undercutting the credibility of a federal agent who helped reveal the botched arms-trafficking probe called Operation Fast and Furious, the Justice Department’s inspector general said Monday.

There was substantial evidence in the 2011 incident that then-U.S. Attorney Dennis Burke’s motive for disclosing a memo by federal agent John Dodson was retaliation, the inspector general’s report said. In testimony to a House committee just two weeks earlier, Dodson had raised serious concerns about Operation Fast and Furious.

In Dodson’s memo, which was eventually leaked, Dodson proposed a tactic similar to the one being used at the time in Operation Fast and Furious. Dodson proposed acting in an undercover capacity to deliver firearms to a suspected firearms trafficker, but taking no enforcement action on delivering the firearms.

Dodson later told investigators that he and other ATF agents had proposed the transaction in hopes it would shock their superiors into realizing what they were doing in Operation Fast and Furious. Instead, a superior approved Dodson’s proposal and Dodson sold six firearms to the suspect. Dodson later told investigators he regretted delivering the firearms.

The Fast and Furious operation used a tactic called gun-walking in an attempt to follow illicit gun buyers to major arms traffickers and dismantle the gun rings supplying weapons to drug cartels in Mexico. The tracking effort was largely unsuccessful, and hundreds of weapons wound up at crime scenes in the United States and Mexico. Two of the weapons were found at the site of the slaying of U.S. border agent Brian Terry.

After Terry’s death, Dodson and several other agents from the U.S. Bureau of Alcohol, Tobacco, Firearms and Explosives described the gun-walking tactic to U.S. Sen. Chuck Grassley, R-Iowa, and to the House Oversight and Government Reform Committee.

As the controversy grew, Burke and Justice Department officials exchanged emails about Dodson’s earlier memo, the report said.

“Unbelievable,” Burke said in one message. “This guy called Grassley and CBS to unearth what he in fact was proposing to do by himself. When you thought the hypocrisy of this whole matter had hit the limit already…”

The report noted that in a separate incident, Burke had told the deputy attorney general that he had improperly disclosed information to the New York Times about a criminal suspect in Operation Fast and Furious.

According to the IG, Burke knew at the time of his disclosure of the Dodson memorandum that he was under investigation by the department’s Office of Professional Responsibility for that earlier leak.

The inspector general’s office is referring its report to OPR to determine whether Burke’s conduct violated rules in the states where Burke is licensed to practice law.