Rep. Darrell Issa [contends] that the Department of Justice in Washington and perhaps the Obama White House were aware of the flawed tactics in the ATF's Fast and Furious gun-tracking operation in Arizona that allowed more than 2,000 firearms to walk" into the hands of Mexican drug cartels. A month before the operation was stopped, U.S. Border Patrol Agent Terry was killed in a December 2010 shootout and two Fast and Furious weapons were discovered at the crime scene between the Mexican border and Tucson. Scores of more weapons have been found at violent crimes in Mexico. Issa contends [that] wiretap documents, signed by top Justice officials in support of Fast and Furious, are proof that administration officials knew the tactics were flawed and should have stopped the operation long before the agent and others were killed. "The tactics of Fast and Furious were known," he said. "They were known and are contained in these wiretaps." Issa said he obtained the materials from "a furious group of whistle-blowers" who are angry with the Justice Department and Atty. Gen. Eric H. Holder Jr. for not providing more material to Issa's investigation into Fast and Furious. The whistle-blowers, he told Holder at the hearing, "are tired of your stonewalling."