Hired to Kill: What Does It Take to Be a Hit Man?

March 13, 2014— -- In every corner of America right now, people with criminal minds are plotting, looking for someone to do their dirty work -- from scorned lovers or husbands who want their wives dead to women who want their husbands taken out and children plotting against their own parents.

Five men recently gave ABC News' "20/20" anchor David Muir an exclusive on-camera look into the dark world of murder for hire. These men all have a secret: They are part of ATF's undercover team and have posed as hit men.

The men, who "20/20" is referring to as "Wayne," "Curtis," "Ken" and "Jose," were in disguise. Only Lenny, who no longer works undercover, was not in disguise and used his real name. Their identities cannot be revealed because doing so could put their lives at risk. These men all have been hired to kill.

"These are dark, dark-hearted people," said Lenny of those who hired them as hit men.

"Just like you'd go to find a plumber to come to your house and fix a pipe, they're looking for an expert to take care of their problem," Ken said.

"I think they're looking for somebody that will do something that they're not willing to do, that they're not capable of doing," Curtis said.

This secret world of fake hit men run by the ATF was first uncovered by writer Jeanne Marie Laskas for GQ Magazine.

"They employ an army of agents who work undercover, who we're not supposed to know about, who pretend to be hit men," Laskas told "20/20." "People hire them to kill someone or to blow something up, or to maim someone, and they go along with it. They sometimes take the payment and then they don't go along with it, arrest the bad guy, put him in the slammer."

Posing as hit men can also take a toll on the agents' personal lives.

"Some of the guys I talked to, their families maybe know that they're a police officer, but they don't really know the extent of it," Laskas said. "So ... it's a very mysterious kind of life."

When going undercover, the men also assume a whole new identity.

"This job numbs you," Jose said. "You become suspicious of everyone."

"I generally will say I'm in law enforcement," Ken said.

The hit men can't be found on Craigslist or in the phone book. Their business, like so many others, thrives on referrals. Undercover ATF agent Ken was hired to kill the wife of Guillermo Vasco.

When Vasco's wife wanted to leave him for good, he showed up at his wife's house and attempted to kill her, but she managed to escape. Vasco was arrested, and a year later, while sitting in prison awaiting trial, he began asking other inmates if they knew a good hit man. One of those inmates was a confidential informant who tipped off the ATF. Ken then went into the prison posing as a hit man to meet with Vasco.

"He wanted her to suffer before she was killed," Ken said. "And he wanted to know the last thing she said before she died."

While some suspects offer money in exchange for a hit, others offered payment in a form the agents were not expecting. Vasco offered Ken his rare coin collection to kill his wife. In one of Lenny's ATF assignments undercover as a hit man, a suspect offered him his motorcycle in exchange for killing a witness against him.

The ATF approached Vasco's wife, who agreed to help them catch her husband. They had her makeup done to look like she'd been attacked and shot in the head and took her to the woods to be photographed. Ken returned to the prison and showed Vasco the photos of his seemingly dead wife.

"There was joy and evil in his face at the satisfaction of knowing she was dead," Ken said.

The undercover team confronted Vasco at the prison, telling him at first that his wife had disappeared. When he denied knowing anything, they decided to bring in Ken.

"You could just see his shoulders slump, his head kind of drop down," Ken said. "Tears started coming out, and he knew he had been had."

"When someone's being so evil next to you, it's like, 'How can you even conceive of something like this?'" Jose said.

The ATF undercover agents all risk their lives for these assignments, but they are also husbands and fathers who reassure their families as best they can.

"I tell them there's a lot of good people out there that are watching my back," Ken said. "And they're going to make sure I go home every night."