Investigations into a gunrunning sting gone horribly wrong are creeping closer to the top of the U.S. Justice Department and its head, U.S. Attorney General Eric H. Holder, Jr.

New documents, released this week, indicate that Holder may have lied to Congress about how much and when he knew about the sting, known as Operation Fast and Furious, in which U.S. Bureau of Alcohol, Tobacco, and Firearms (ATF) agents allowed more than 2,000 firearms to "walk" across the U.S. border to Mexico and into the hands of Mexico’s brutal drug cartels.

As many as 1,700 of those weapons have since been lost, and more than 100 have been found at bloody crime scenes on both sides of the border, including at the murder site of a U.S. Border Patrol agent in Arizona last December. The sting is now the subject of a Congressional investigation to find out who was responsible for or knew about the operation.

In May 2011, Holder testified before Congress that he "probably heard about Fast and Furious for the first time over the last few weeks." But new evidence reveals that Holder was informed that guns were being "walked" into Mexico at least nine months earlier.

The memos, sent by the National Drug Intelligence Center and Asst. AG Lanny Breuer, indicate that high-level DOJ officials, including Holder, were fully aware that guns were being "walked" into Mexico.

"Straw purchasers are responsible for the purchase of 1,500 firearms that were then supplied to Mexican drug trafficking cartels," states a July 2010 memo, addressed to Holder. "They also have direct ties to the Sinaloa Cartel which is suspected of providing $1 million for the purchase of firearms in the greater Phoenix area."

The memo leaves no doubt that senior DOJ officials knew the guns were going straight into the hands of Mexico's violent organized crime gangs. Several agents have testified that the cartel leaders targeted by Fast and Furious were allegedly paid informants for the DEA and the FBI.

The GOP is now turning up the heat on Holder, who it appears may have actually perjured himself. House Oversight Chair Darrell Issa, the Republican leading the investigation, is now demanding Holder "come forward and at least admit" he knew about Fast and Furious.

"He implied he knew nothing when in fact he at least knew something,” Issa said on Fox News yesterday. "“We certainly would like to believe that he was disingenuous but not lying. The fact is, the people who are making those statements on his behalf are lying on his behalf, period.”

There are indications the Obama administration may be cracking under the pressure — CBS reporter Sharyl Attkisson said yesterday that White House spokesman Eric Schultz "screamed and cussed" at her over a story she published on Fast and Furious. Press Secretary Jay Carney dismissed the allegations, adding that "hard-bitten journalists" should be able to handle "an extra decibel or two."

And amid the expanding scandal, the head of the ATF announced a major shakeup at the agency yesterday, appointing 11 new people to high-level positions, including deputy director and assistant field directors.

But the White House has been steadfast in its defense of Holder, who is a close confidante of Obama. Press Secretary Jay Carney told reporters yesterday that the President "has great confidence" in Holder and believes his testimony "was consistent and truthful."