The chairman of the House Committee on Oversight and Government Reform is threatening contempt proceedings against the acting director of the Bureau of Alcohol, Tobacco, Firearms and Explosives (ATF) for "failing to cooperate in good faith" with his committee's investigation. Rep. Darrell Issa, R-Calif., sent a letter to ATF acting Director Kenneth Melson threatening the action after Issa says the agency "failed to produce any documents" in response to a March 31st subpoena.

"I am disappointed that you have failed to produce any documents that would meet your legal obligations by the subpoena's April 13th deadline," he wrote in the letter.

Click here for the letter in PDF form

Issa says the Justice Department has held on to the requested documents claiming that they are a part of an open investigation and thus, can't be released. But Issa disagrees with that assertion.

"The Department's internal policy to withhold documents from what it labels pending criminal investigations may not deprive Congress from obtaining those same documents if they are pertinent to a congressional investigation - particularly in a matter involving allegations that reckless and inappropriate decisions by top Justice Department officials may have contributed to the deaths of both U.S. and Mexican citizens," he wrote.

The congressional investigation focuses on Operation Gun Runner, an ATF sting operation targeting gun trafficking along the Mexican border. A pair of AK-47 assault rifles used in the sting later turned up alongside body of a murdered U.S. Border Patrol agent in Arizona. Issa wants to know if the operation contributed to the agent's death.

"Efforts by the Department of Justice and ATF to stonewall the Committee in its investigation by erroneously, but matter-of-factly, citing an internal department policy as a preventative measure for denying access to documents have only enhanced suspicions that such officials have played a role in reckless decisions that have put lives at risk," Issa wrote. "Let me be clear ... we are not conducting a concurrent investigation with the Department of Justice, but rather an independent investigation of the Department of Justice..."

Issa noted in the letter that Sen. Chuck Grassley, R-Iowa, the ranking member of the Senate Judiciary Committee requested documents relating to the case as far back as January. Grassley has expressed concerns over the Justice Department's ability to provide a "frank and unbiased" investigation of the case.