Sen. John McCain has requested a Congressional hearing on the much-maligned gun trafficking investigation led by the ATF.

Up until recently, two fellow Republican legislators — Sen. Charles Grassley, R-Iowa, and Rep. Darrell Issa, R-Calif., — have led the Congressional inquiries into the Bureau of Alcohol, Tobacco, Firearms and Explosives' "Fast and Furious" operation.

In a letter sent Wednesday, McCain said additional information released about the operation last week warrants a hearing of the Senate Homeland Security and Governmental Affairs Committee, of which McCain is a member.

“The committee should hold a meeting as soon as possible to examine these new revelations and determine what additional measures are needed to help prevent this type of malfeasance from occurring again,” McCain wrote in a letter addressed to Sen. Joe Lieberman, I-Conn., and Sen. Susan Collins, R-Maine. 

The veteran Arizona Senator is asking for the committee to call the U.S. Attorney General, Eric Holder; the Homeland Security Secretary, Janet Napolitano; and the ATF’s acting director, B. Todd Jones; as witnesses.

Issa and Grassley leveled new criticism of the operation recently, saying the U.S. Attorney's Office in Arizona tried to downplay downplay the link between two guns found at the scene of a Tucson Border Patrol agent's fatal shooting and the 'Fast and Furious' investigation.

The duo launched a congressional inquiry into the ATF operation early this year after learning two assault rifles recovered at the scene of the Dec. 14 killing of Agent Brian Terry near Nogales had been sold to straw buyers in Phoenix and tracked into Mexico under the ATF operation.

In "Fast and Furious," officials allowed guns to be bought by "straw purchasers" with the goal of busting high-level operatives in Mexico.

But officials admitted they had lost track of more than half of the 2,000-plus weapons in the operation.

Straw purchases - when gun smugglers pay someone with no criminal record to buy a gun from a licensed dealer - make up a significant portion of illegal gun sales and fuel gun smuggling from the U.S. to Mexico.

If McCain's request is granted, it would not be the first Congessional hearing about the operation. The House Oversight and Government Reform Committee has held two hearings on the operation — one on June 15 and the other on July 26.