Updated

The Justice Department on Friday provided Congress with documents detailing how the department gave inaccurate information to a U.S. senator in the controversy surrounding Operation Fast and Furious, the flawed law enforcement initiative aimed at dismantling major arms trafficking networks on the Southwest border.

In a letter last February to Charles Grassley, the ranking Republican on the Senate Judiciary Committee, the Justice Department said that the Bureau of Alcohol, Tobacco and Firearms had not sanctioned the sale of assault weapons to a straw purchaser and that the agency makes every effort to intercept weapons that have been purchased illegally. In connection with Operation Fast and Furious, both statements have turned out to be incorrect.

In a letter to the ATF last January, Grassley said the Senate Judiciary Committee had received allegations that the law enforcement agency had sanctioned the sale of hundreds of assault weapons to suspected straw purchasers. Grassley also wrote that two of the guns had been used in a shootout that killed customs agent Brian Terry.

In a subsequent email to Justice Department colleagues, then-U.S. Attorney Dennis Burke in Phoenix said that "Grassley's assertions regarding the Arizona investigation and the weapons recovered" at the "murder scene are based on categorical falsehoods. I worry that ATF will take 8 months to answer this when they should be refuting its underlying accusations right now." That email marked the start of an internal debate in the Justice Department over how much to say in response to Grassley's allegations. The fact that there was an ongoing criminal investigation into Terry's murder prompted some at the Justice Department to argue for less disclosure.

It is unusual for the Justice Department to provide the details of its internal deliberations.

The Justice Department provided 1,364 pages of documents to Congress after concluding "that we will make a rare exception to the department's recognized protocols and provide you with information related to how the inaccurate information came to be included in the letter," Deputy Attorney General James Cole wrote Grassley and Rep. Darrell Issa, R-Calif., chairman of the House Oversight and Government Reform Committee, which is looking into the Obama administration's handling of Operation Fast and Furious.