Sen. John McCain is asking for a Senate hearing on the ATF's Fast and Furious "Gunwalker" scandal "as soon as possible."
And he wants Attorney General Eric Holder to testify.
In a letter to the Chairman of the Senate Homeland Security Committee Joe Lieberman, McCain calls Operation Fast and Furious "ill conceived and poorly implemented."
As CBS News first reported last February, the Bureau of Alcohol, Tobacco, Firearms and Explosives allegedly allowed thousands of weapons to "walk" onto the streets without interdiction into the hands of suspected traffickers for Mexican drug cartels.
The operation allegedly had the blessing of the lead prosecutor on the case. That prosecutor, Emory Hurley, was recently reassigned. Last week, his boss U.S. Attorney Dennis Burke resigned, as did the head of ATF Kenneth Melson.
This week, the Department of Justice removed Fast and Furious and two related cases from the US Attorney's office in Arizona and reassigned them to California prosecutors.
McCain's letter states that a hearing is needed "to ensure that further damage from this operation does not persist." He says witnesses should include Holder, the Secretary of Homeland Security Janet Napolitano, and the Acting Director of ATF Todd Jones.
Holder has not given detailed testimony on the scandal. He had no comment on McCain's request. President Obama has said that neither he nor Holder knew about or approved of the operation. The Inspector General is investigating.