In retrospect, Tony Coulson didn't fully grasp what he was getting into, he says.

Back in February, Coulson, who retired as head of the DEA's Tucson office in 2010, did an interview with Michel Marizco, a former Arizona Daily Star staffer now working for public radio's Fronteras Desk. In that piece, Coulson said that he and others in federal law enforcement knew about ATF's practice of allowing guns loose into Mexico. He also said that border inspectors in Arizona had seized two loads of guns that were part of the probe and that he'd passed his concerns about the tactic to his boss in DEA.

Coulson's perspective was a new twist for reporters who have followed the notorious Operation Fast and Furious, so it led to more interviews, and a minor spate of news stories or commentaries. Coulson's comments led to more conclusions that Operation Fast and Furious was part of a larger plot to impose gun control in America, a common suspicion of some Obama administration critics.

When William La Jeunesse of Fox News asked to interview him, Coulson said, Coulson asked for some assurances about the context that the reporter would put the story in. Coulson was disappointed when the story came out that the timeline of his story was not included and a quote about one topic was printed as a reference to another, he said.

Also, congressional investigators called to talk to him. When Coulson clarified that he knew ATF "gun walking" going on in 2008, before Obama took office, you could "hear them not be interested in the story anymore."

"I was naive to the fact that there was an agenda I had no control over. Whatever I said had to fit into that agenda," he said.

Beth Levine, the spokeswoman for Sen. Charles Grassley, said the senator, who brought Fast and Furious to light, cannot be accused of ignoring gun-walking under the Bush administration. She noted he has repeatedly delved into Operation Wide Receiver, a Tucson-based ATF investigation that preceded Fast and Furious and began in the Bush administration.

On Jan. 5, Grassley said in a statement, " I’ve said all along that walking guns is wrong, period.  I don’t care who did it."

I spoke with Coulson for my recent story about the decrease in drug-war gun-battles in Nogales, Sonora. After we discussed that, he clarified his views on what was going on with Operation Fast and Furious, which he didn't know by name at the time he saw it happening. He knew it only as Operation Gunrunner, the broader name for the effort to stop guns from being smuggled into Mexico, and he pegged its excesses on the man who ran the Phoenix office of the ATF, Bill Newell.

"I don’t think there was any big conspiracy by Eric Holder or anybody on Fast and Furious. I think there was a little deliberate ignorance. This was Bill Newell and a couple of agents in Arizona who had carte blanche," Coulson told me.

Operation Fast and Furious was an ill-conceived gun-smuggling sting by agents of the Bureau of Alcohol, Tobacco, Firearms and Explosives. It began in 2009 in Phoenix and ended with indictments in January 2011. In between, agents facilitated the transfer of about 2,000 weapons, many of them high-powered rifles, to people suspected of buying them for Mexican drug traffickers.