A well-known whistle-blower in the Bureau of Alcohol, Tobacco, Firearms and Explosives confirmed to FoxNews.com that he was fired this week, and he claims his complaints about Operation Fast and Furious played a role in his dismissal.
Vince Cefalu said he was served his termination papers Tuesday in a Denny's parking lot in South Lake Tahoe, Calif. But he doesn't plan to go quietly.
"It will be challenged," he said.
Cefalu, who's served as an ATF special agent for 25 years, was first notified of the plan to fire him more than a year ago but had been on administrative leave until now. He said officials told him he was being canned for "lack of candor," in reference to a handful of statements he made in testimony in a separate court case.
However, Cefalu has been outspoken against ATF practices for years and told FoxNews.com that his whistle-blowing on Fast and Furious "was the final straw."
'Project Gunrunner' Whistleblower Says ATF Sent Him Termination Notice
Ex-security officers testify about frustration at State Department over Libya security
Fox News poll: 53 percent say Obama failed on economy, Libya 'troubling'
Rep questions State Department's green energy spending amid security concerns
Cefalu was one of the founders of the website CleanUpATF, a virtual platform for complaints about the agency. He was among the first to speak up about Fast and Furious, the failed anti-gunrunning operation that let thousands of guns slip across the U.S.-Mexico border. Weapons from the program were founded at the murder scene of Border Patrol Agent Brian Terry.
An inspector general report on the operation released in September was highly critical of both the ATF and officials at the Justice Department.
The ATF, though, has previously denied that it was retaliating against Cefalu.
ATF spokesman Drew Wade confirmed that Cefalu "separated" from the agency on Tuesday, though Wade could not comment further.
"Because of privacy laws and internal policies, we can't talk about personnel matters," he said.
Cefalu's first run-in with higher-ups at ATF came when he objected to what he considered to be an illegal wiretap in a 2005 case unrelated to Fast and Furious, which didn't launch until years later.
He told FoxNews.com last year that those complaints marked "the beginning of the end."