And, back to Gunwalker, CBS News has learned that House and Senate investigators

have descended upon Arizona for their probe into the so-called "Gunwalker" scandal. They're gathering interviews from witnesses, including ATF insiders and area gun shop owners.
And why might they be doing that?
Government officials have said they won't provide information while their own investigations are ongoing.

"They're investigating themselves," says one source on Capitol Hill, "and then claiming the open investigations preclude them from giving Congress information it needs for independent oversight. It's highly improper."
Sure as hell is. For that matter, refusing to obey a subpoena is, I think, a crime; can't get much more improper than that when you're a LE agency.

As to the claims Napolitano and Obama & Holder knew nothing about it,
Sources and documents indicate the prosecutor who advised the "Fast and Furious" case in Phoenix was Asst. U.S. Attorney Emory Hurley. His boss, Arizona's US Attorney Dennis Burke, was a longtime chief of staff for Homeland Security Chief Janet Napolitano when she served as Arizona governor. In brief questioning from Congress in March, Napolitano said it was "premature" to comment on details of the Fast and Furious controversies. She also said she was "not aware" that an agent under Homeland Security was on the ATF Fast and Furious task force in Phoenix. Speaking of herself in the third person, Napolitano stated that "no concerns were expressed to the Secretary."(you believe any of that? Me neither)
...
ATF's former lead agent in Mexico, Attache Darren Gil, told CBS News in an exclusive interview that he believes senior Justice Dept. official Lanny Breuer and several of his deputies who visited Mexico amid the controversy last summer knew all about the alleged gunwalking, as did ATF's Acting Director Kenneth Melson. None of those officials would speak to CBS News. Federal agencies have refused Congressional requests to turn over documents related to the official's Mexico trips.
They really, really don't want to talk about this, do they? Makes me wonder what'll happen when they're put under oath.