Undercover ATF Agent on the Assignment No One Else Wanted

March 14, 2014— -- After a drug dealer was arrested in a drug bust and looked for a hit man while in prison, an ATF agent went on an assignment that no other agent wanted to take.

Working as an informant for the ATF is a dangerous job; just ask Dave Jackson. His involvement in an undercover operation to take down Virginia drug dealer James Robert Hackley almost cost him his life.

After Hackley landed in jail for selling drugs, Jackson found himself on the wrong side of a dangerous criminal. From behind bars, Hackley began asking other inmates to recommend a good hit man to take out Jackson. When the ATF learned that the drug dealer was looking for someone to do a hit job, they sent one of their agents, Lenny, into the jail posing as an inmate.

"We planned this case out meticulously. And as we were getting ready to do the strip search, that's when I thought, 'I didn't think this through,'" Lenny said.

Sheriff Daniel McEathron was one of only two people who knew Lenny was an undercover ATF agent.

"There's a lot of things that could go wrong," McEathron told "20/20." "When you're dealing with a lot of inmates in one area, you never know what might happen and transpire."

In order to nab the dealer who wanted to hire a hit man, Lenny had to do what every other inmate did. This included using the communal toilets and even stealing a bunk from another inmate in the overcrowded prison.

"I just had to displace somebody else and take their bed to make theirs mine," Lenny said.

Eventually, word got back to Hackley that there was a hit man for hire behind bars. Another inmate and ATF informant told Hackley that Lenny killed people in the past and hadn't been caught.

"The informant goes over and says [to Hackley], 'Hey man, I know you're having issues with that guy outside. This guy has got bodies hanging,'" Lenny said.

After that, Hackley immediately contacted Lenny.

"He says, 'I need this guy taken out.' I'm like, 'Well, what do you mean by taken out?'" Lenny recalled. "'I need him gone forever; I need him, you know, eliminated.'"

While all the guards and inmates thought Lenny was an actual criminal, he knew he had the prison's surveillance cameras on his side. But suddenly, an unexpected storm caused those surveillance cameras to go dark.

"So I'm in here without cover, without any backup," Lenny said. "The evacuation plan that we had is totally gone at that point."

Even in the dark, Lenny made a deal and was hired by Hackley to kill Dave Jackson. Hackley said he'd pay him with a motorcycle. After the ATF cover team got Lenny out of jail, he headed to an apartment where Hackley's girlfriend was going to show him proof that the motorcycle existed. She gave Lenny a key to the as a down payment for the murder. All that was left was for Lenny to deliver on his end of the bargain and eliminate the informant, Dave Jackson.

"They came to me and said, 'Look, we're going to fake your death,'" Jackson told "20/20." Federal agents took photos of Jackson, who was made to look like he was killed in a drive-by shooting.

The ATF then included the photo in a fake newspaper article about Jackson's supposed murder that was sent to Hackley in jail.

"I love you man," Hackley could be heard telling another informant on an ATF tape recording. "I owe you my life. You know I do."

In addition to the drug charges Hackley was already facing, the ATF investigation resulted in additional solicitation of murder for hire charges. In 2010, Hackley was sentenced to more than 25 years in prison.

Lenny no longer works undercover, but he knows there are very real dangers that exist in the places you least expect it.

"We're in middle day, modern America," said Lenny. "You have kids playing all around you, and there's nefarious individuals planning out murders and hits."