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Top Department of Justice officials had extensive knowledge of and involvement in Operation Fast and Furious, claims a new report released Thursday, hours before Attorney General Eric Holder's scheduled testimony to the House Oversight and Government Reform Committee.

The report released by Rep. Darrell Issa, R-Calif., and Sen. Charles Grassley, R-Iowa, top lawmakers investigating the botched gunrunning operation, claims Justice Department officials in Washington and the Bureau of Alcohol, Tobacco, Firearms and Explosives were involved in the coordination in the early stages of the operation.

Justice headquarters "had much greater knowledge of, and involvement in, Fast and Furious than it has previously acknowledged," the memo reads.

The memo, which contradicts claims by the Justice Department, is based upon interviews, documents and emails involving key players of the operation run by the ATF. The operation allowed some 2,000 weapons cross the border into Mexico and into the hands of cartel members.

Two of the weapons linked to the program were found at the murder scene of U.S. Border Patrol Agent Brian Terry in 2010 as well as other crime scenes in Mexico.

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Emails released show that Kenneth Melson, former acting director of the ATF, contacted Assistant Attorney General Lanny Breuer and told him that his organization wanted to take a "different approach" to seizing guns going to Mexico.

Breuer responded that it was a "terrific idea" and the department assigned a prosecutor from its Criminal Division to work with the ATF in early 2010.

But in the wake of accusations by Issa against the department, Deputy Attorney General James Cole wrote Issa on Wednesday, rejecting assertions that Breuer wanted the Phoenix division of ATF to participate in gun-walking

"In light of Assistant Attorney General Breuer's commitment to stemming the flow of guns from the United States into Mexico and his strong ties and collaborative relationships with his counterparts in Mexico, it is inconceivable that his intention was to have guns released into Mexico," Cole wrote.

Republicans say attorney Joe Cooley attended key briefings on the program and should have alerted the Justice Department to what was going on. The memo also alleges that there was a lack of management by both the ATF and Justice Department with the use of federal wiretaps.

"Both Justice Department and ATF leaders in Washington, D.C., claimed they were unaware of the gun-walking that occurred during Fast and Furious, yet both could have and should have reviewed the wiretap affidavits," reads the memo.

Congressional investigators also say the Criminal Division of Justice Department had knowledge of a previous gun trafficking operation named "Wide Receiver" and should have drawn a parallel between the two. Officials in that department have claimed that they did raise concerns about Operation Wide Receiver and alerted the ATF.

Thursday's report also criticizes Holder’s current chief of staff Gary Grindler, who served as Acting Deputy Attorney General during part of Operation Fast and Furious. According to Grindler's testimony, he says he knew little about Fast and Furious and assigned oversight of the ATF to two deputies. Grindler told investigators that he expected his associates to bring any problems to his attention.

The memo also repeated claims that the Justice Department was "managing the congressional investigation in order to protect the political appointees at the department."

In his testimony prepared for Thursday's hearing, the attorney general said that prior administrations have recognized that robust internal communications would be chilled, and the executive branch's ability to respond to oversight requests impeded, if internal communications concerning responses to congressional oversight were disclosed to Congress.