"The allegation described in your January 27 letter — that ATF 'sanctioned' or otherwise knowingly allowed the sale of assault weapons to a straw purchaser who then transported them into Mexico — is false," the letter said.
Since then, Issa's panel has revealed scores of documents and, in a June 15 hearing, heard the testimony of four ATF agents who described orders to allow the straw purchases that had been alleged.
At the most recent hearing on the issue — on July 26 — Issa's foil on the committee, ranking member Elijah Cummings, skeptically demanded answers from a panel of mid-level ATF officials, showing his impatience at times. "Well, that was more than a little bit of extra time, was it not?" the Maryland Democrat asked, pressing about why Fast and Furious wasn't shut down more quickly.
His questioning marked a change in tone. At a June 15 hearing, Cummings apologized to a DOJ witness after a round of angry questioning by Issa.
Ashley Etienne, a spokeswoman for Cummings, said her boss had been "incredibly" consistent on the investigation, pushing to "uncover any wrongdoing" while "ensuring that we don't compromise the ongoing criminal investigation."
Issa suggested there is more to come on Fast and Furious.
"Perhaps within my investigation team, there's a considerable amount of knowledge we have that we're still waiting for them to turn over pursuant to subpoena. That would be reasonable to expect," Issa said last week. "Because, so far, every black redacted page they gave us, virtually, I have the unredacted version first and that's why we asked for it."
Issa also recently scored blows in a fight with the New York Times over a front-page story by reporter Eric Lichtblau.
The four corrections that the paper issue related to the story boosted morale among Issa's nearly 80-member committee staff. "People were coming out of the woodwork. All these people I would have never guessed were writing me to say, 'Wow, the New York Times looks really bad here,'" Hill said.
Democrats say Issa has a long way to go before he can call it a comeback.
His critics highlight investigations dropped without explanation.
The panel had scheduled a July 13 hearing on the Financial Crisis Inquiry Commission, charged with investigating the causes of the financial crisis of 2008.
Issa wondered in a release whether the FCIC and its staff "may have conflicts of interest" preventing an "even-handed investigation." Issa obtained more than 400,000 documents from the commission and scheduled the hearing to grill Democrat Phil Angelides, the chairman of the commission and a former California treasurer.
Angelides had already flown from California to Washington, D.C., when an Issa aide called to tell him the hearing had been postponed.
Angelides' attorney said the aide told him that the panel had found documents that didn't "fit their narrative."
Hill said such an account was "not accurate."
The hearing has not been rescheduled.
A subsequent report from Cummings and his staff revealed embarrassing details about how the Republicans on the FCIC had behaved, illustrating how a probe might be politically inconvenient.
Other investigations are missing in action.
There's an inquiry into VIP loans from Countrywide Financial. "That's a scandal that isn't finished yet," Issa said the night Republicans won the House. Issa subpoenaed documents in February but has made no other public moves.