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Despite a federal holiday, the lawmaker leading a congressional investigation into "Operation Fast and Furious" launched his latest salvo Monday against Attorney General Eric Holder, insisting it's time for the nation's top cop to "come clean to the American public about what you knew, when you knew it, and who is going to be held accountable."

"Whether you realize yet or not, you own 'Fast and Furious,'" Rep. Darrell Issa, R-Calif., said in a letter to Holder. "It is your responsibility."

The reply comes three days after Holder responded in his own letter to questions over whether he misled Congress in May when he told lawmakers he "probably heard about Fast and Furious for the first time over the last few weeks."

A week ago, the ranking Republican on the Senate Judiciary Committee, Sen. Charles Grassley, R-Iowa, distributed five memos from July and August 2010 addressed to Holder, citing the gun-running investigation by name.

In his letter Friday, Holder said his remarks on "Fast and Furious" have been "truthful and accurate," adding, "I have no recollection of knowing about 'Fast and Furious' or of hearing its name prior to the public controversy about it. ... Prior to early 2011, I certainly never knew about the tactics employed in the operation."

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But Issa insisted in his latest response that "the current paper trail ... creates the strong perception that your statement in front of Congress was less than truthful." The chairman laid out a series of instances that he said shows high-level knowledge of "Fast and Furious."

The broader back-and-forth focuses on a Bureau of Alcohol, Tobacco, Firearms and Explosives investigation in Arizona targeting major gun-runners. Launched in late 2009, the investigation planned to follow gun purchasers in hopes that suspects would lead them to the heads of Mexican cartels. But high-powered weapons tied to the investigation ended up at crime scenes in Mexico and the United States, including the murder of Border Patrol Agent Brian Terry late last year.

In his letter Monday, Issa cited several documents and briefings of Justice Department officials that referenced large purchases of weapons by suspects. Such newly disclosed documents, Issa said, "directly contradict" Holder's insistence that "Fast and Furious" did not reach into the upper levels of the Justice Department.

"Your staff ... was certainly aware of 'Fast and Furious' over a year ago," Issa wrote, without citing any documents or briefings where controversial tactics were specifically mentioned.

"Gary Grindler, the then-Deputy Attorney General and currently your chief of staff, received an extremely detailed briefing on 'Operation Fast and Furious' on March 12, 2010," Issa said in his letter. "In this briefing, Grindler learned such minutiae as the number of times that Uriel Patino, a straw purchaser on food stamps who ultimately acquired 720 firearms, went in to a cooperating gun store and the amount of guns that he had bought. When former Acting ATF Director Ken Melson, a career federal prosecutor, learned similar information, he became sick to his stomach."

According to the Justice Department, however, Melson is the one who briefed Grindler, and, according to Issa, it was not until months later Melson learned of the tactics that made him "sick to his stomach."

In fact, Grindler's heavily redacted notes from the briefing reference "Fast and Furious" by name, multiple weapons sales and "seizures in Mexico," but the publicly disclosed portions of the briefing and Grindler's notes do not reference the controversial tactics known as "gun-walking."

In his letter Friday, Holder said Grindler's briefing was "much like" presentations given to others in 2010, including one briefing to Issa in April 2010.

"(Grindler's briefing) did not reveal the problematic investigative tactics that were apparently being used that allowed guns to cross the border into Mexico," Holder wrote. "Indeed, as both the former U.S. attorney in Arizona and the former acting director of ATF have made clear, they did not themselves know the operational details and did not brief Justice officials on them."

Issa, meanwhile, wasn't convinced, insisting there was "widespread knowledge" within the Justice Department's "senior ranks" that "gun-walking" was "occurring." He said Holder, with his letter Friday, tried to "shift blame" and "hide behind" his staff "for failing to inform you about 'Operation Fast and Furious' when they reviewed the memos sent to you last summer."

"It simply is not believable that you were not briefed on 'Fast and Furious' until a few weeks before your testimony," Issa told Holder on Monday. "At the very least, you should have known about Fast and Furious well before then.

According to Holder, such statements "mischaracterize the process by which I receive information concerning the activities of the department's many components."

He said his office typically receives more than 100 pages of "so-called 'weekly reports' that, while addressed to me, actually are provided to and reviewed by" his staff and the deputy attorney general's staff. He said he does not "and cannot read them cover-to-cover."

"Please note that none of these summaries (recently disclosed) say anything about the unacceptable tactics employed by ATF," he wrote. And, he said, "No issues concerning Fast and Furious were brought to my attention because the information presented in the reports did not suggest a problem."

A Justice Department spokesman added Monday that Issa's allegations are "recycled" and "baseless."

"The department will continue to cooperate with both the inspector general and congressional investigations. In the meantime, what the American people deserve is less partisan showboating and more responsible solutions to stopping gun violence on the Southwest border," the spokeswoman said.

For Issa, Holder's latest defense is part of what he called "a roving set of ever-changing explanations to justify (the Justice Department's) involvement in this reckless and deadly program."

"Your letter ... did little but obfuscate, shift blame, berate, and attempt to change the topic away from the department's responsibility in the creation, implementation, and authorization of this reckless program," Issa wrote. "You claim that, after months of silence, you 'must now address these issues' over Fast and Furious because of the harmful discourse of the past few days. Yet, the only major development of these past few days has been the release of multiple documents showing that you and your senior staff had been briefed, on numerous occasions, about 'Fast and Furious.'"

Issa also said the Justice Department's cooperation with his investigation "has been minimal," adding that many of the documents provided have been "duplicative" and heavily redacted.

Appearing on "Fox News Sunday" over the weekend, Issa confirmed he will be sending a new set of subpoenas to the Justice Department, seeking further information.

In addition to the congressional investigation being led by Issa and Sen. Charles Grassley, R-Iowa, House Judiciary Committee Chairman Lamar Smith, R-Texas, is calling for a special counsel to look into the matter.