Updated

The Bureau of Alcohol, Tobacco and Firearms is being accused of retaliating against an agent who helped publicize the agency’s role in allowing thousands of guns to cross the U.S. border and fall into the hands of Mexican drug gangs.

The agent, Vince Cefalu, who has spoken out about the ATF's so-called "Project Gunrunner" scandal, says he was served with termination papers just last week, and he calls the move politically motivated.

“Aside from Jay Dobyns, I don't know of anyone that's been more vocal about ATF mismanagement than me,” said Cefalu, a senior special agent based in Dublin, Calif. “That's why this is happening.” Dobyns, an ATF special agent based in Tucson, has appeared several times on Fox News to discuss the scandal.

Cefalu first told FoxNews.com about the ATF’s embattled anti-gun smuggling operation in December, before the first reports on the story appeared in February. “Simply put, we knowingly let hundreds of guns and dozens of identified bad guys go across the border,” Cefalu said at the time.

Since then, Cefalu’s claims have been vindicated, as a number of agents with first-hand knowledge of the case came forward. The scandal over Project Gunrunner led to congressional hearings, a presidential reprimand – Obama called the operation “a serious mistake” – and speculation that ATF chief Ken Melson will resign.

Yet last week, Cefalu, who has worked for the agency for 24 years, was forced to turn in his gun and badge. He can appeal but will be on “paid administrative leave” during the process.

Cefalu’s dismissal follows a string of allegations that the ATF retaliates against whistleblowers. When the Project Gunrunner scandal broke, Sen. Chuck Grassley, R-Iowa, wrote the ATF that an agent who had been giving his staff members information about the scandal had been "allegedly accused... of misconduct" by the agent’s boss for talking with Grassley’s staffers.

And two days before Cefalu was served with termination papers, Rep. Darrell Issa, R-Calif., chairman of the House Committee on Oversight and Government Reform, sent a letter to the ATF warning officials not to retaliate against whistleblowers.

ATF spokesman Drew Wade denied in a statement to FoxNews.com that the bureau is retaliating, but he declined to comment about Cefalu's case. “ATF will not comment on specific, ongoing personnel matters. It is illegal to use disciplinary actions to retaliate against employees, and ATF does not engage in such improper reprisals.”

The ATF's termination letter to Cefalu, obtained by FoxNews.com, makes no mention of Cefalu’s role in the latest scandal.

“You think they would just come out and say that?” Cefalu said.

The letter instead says that Cefalu should be fired because he leaked documents on a website he helped create, CleanupATF.org, and showed a “lack of candor” on past projects, in particular a 2005 operation that Cefalu led. Cefalu admits he made information about the case public but says he did so only after redacting sensitive parts and exhausting internal channels.

In the 2005 case, local police wanted to wiretap a suspect to gather evidence, but Cefalu objected, saying it would be illegal to use wiretaps until all other options for gathering evidence had been tried.

Cefalu was then removed from the case. But he continued to speak out and file internal complaints about what he viewed as illegal ATF wiretapping. And that’s when his life became difficult.

“That was the beginning of the end,” Cefalu told FoxNews.com.

“I had never had a disciplinary action in 18 years. Outstanding evaluations -- above average -- and on the 19th year, when I filed a complaint, I get my first unsatisfactory evaluation ever.”

Cefalu showed a copy of his 2005 evaluation to FoxNews.com, in which his supervisor, Dennis Downs, noted: “Not only have you meet [sic] performance expectations, you have exceeded them.”

But that changed after 2005, Cefalu said. He received unsatisfactory evaluations complaining about his use of foul language. The termination letter also notes there were complaints about his smoking and “even your hygiene.”

Another ATF agent, who requested to remain anonymous but who has provided accurate information on the Project Gunrunner case to FoxNews.com in the past, discussed what he knew about Cefalu.

“Common knowledge in the agency is that Cefalu outed an illegal wiretap quite some time ago, and he has been in the crosshairs since,” the agent told FoxNews.com. “My impression of him is that he has probably ruffled lots of feathers and delicate egos in his time. He is very direct and honest.”

But this agent said he'd “prefer that to a ‘go along to get along’ type."

"We don't avoid or learn from mistakes if we just lie to each other about how we never do anything wrong -- which is pretty much standard operating procedure from what I have seen of our HQ people," the agent said.

Cefalu said his work on the Project Gunrunner scandal likely was the last straw for his bosses.

“I think it’s obvious why they’re doing this. It was my willingness to expose (Project Gunrunner) and support other people to come forward,” Cefalu said.