William Newell, former special agent in charge of the ATF's Phoenix division, at a January press conference announcing indictments in cases that emerged from Operation Fast and Furious.

Matt York, The Associated Press

In November, Sen. Charles Grassley accused former U.S. Attorney Dennis Burke of "whistleblower retaliation" for leaking a memo pertaining to a key ATF agent in Operation Fast and Furious.

At the time, as I mentioned in this blog item, we knew about the leak of the memo, and we knew it apparently led to Burke's resignation in August, but we didn't know what was in it. Now we do, thanks to an apparently coordinated counteroffensive by attorneys for two supervising ATF agents in the Phoenix office.

On March 14, attorneys for David Voth and Bill Newell sent letters to Grassley and Rep. Darrell Issa, accusing them of coming to false conclusions in the service of political goals. Katie Pavlich of Townhall.com posted the leaked letters in this item. You can go straight to the letter from former group supervisor Voth's letter here, and a link to former special agent in charge Newell's letter here.

Both of the DC-based attorneys, Paul Pelletier for Newell and Joshua Levy for Voth, said Dodson himself put guns in the hands of a suspected firearms trafficker, Isaias Fernandez, in June 2010 and let them walk. This was about six months before Dodson became the first ATF agent to blow the whistle on Operation Fast and Furious, after Border Patrol Agent Brian Terry's death. Here's Dodson's March 2011 interview with CBS News.

Here's how Levy, the attorney for Voth, describes Dodson's activities: "SA Dodson knowingly provided six AK Draco pistols to Fernandez, whom the ATF suspected was exporting the firearms to Mexico. Neither SA Dodson, SA Casa nor SA Styers maintained surveillance on those six firearms. SA Dodson took personal leave the very same week that he personally provided the six firearms to Fernandez. Yet there have been no hearings on this case and no mention of it in any congressional report."

Levy goes on to allege that, without receiving necessary prior approval, Dodson had already staged two straw purchases using a confidential informant, in May 2010.

This all matters because it potentially undermines one of the key witnesses against those who have been accused of wrongdoing in Fast and Furious, which allowed close to 2,000 weapons to be sold to suspected straw purchasers. Dodson famously testified before a congressional committee last year that when ATF agents see an illegal gun purchase, they must maintain surveillance. "You don't get to go home," he said.

Levy also says Dodson never objected to his superiors about gun walking as part of Operation Fast and Furious. What he did object to, Levy says, is having to work late and weekend hours monitoring a wiretap of the Fast and Furious suspects. That, Levy says, is what Voth was referring to in his notorious email (attached) describing a "schism" in the group of investigators pursuing Operation Fast and Furious.

Together, the letters constitute the first significant counteroffensive by the ATF targets of the congressional investigation into Operation Fast and Furious.

Their allegations certainly aren't the last word on Dodson and his claims though. They don't, for example, explain why ATF agents in Phoenix went beyond allowing gun sales to go through and instead asked gun-store owners to continue selling to suspected traffickers.