We turn to a rare inside look at the secret underworld after murder for hire. "20/20" anchor David Muir here. You went undercover with those who pose as hit man. Yes. For the first time on network... See More
We turn to a rare inside look at the secret underworld after murder for hire. "20/20" anchor David Muir here. You went undercover with those who pose as hit man. Yes. For the first time on network television a group of these hit men coming forward to talk to us, of course, they're really federal agents and the people all over this country hiring them have no idea and who's doing the hiring? You're about to see the suburban soccer mom from middle America. In every corner of America right now people with criminal minds and black hearts are plotting. Husbands would want their wives dead, women who want their husbands taken out. Even children plotting against their own parents, just listen to this wife. What do you want done? I want him more than hurt. You're saying you want him dead. Dead. Reporter: Witness this husband who wants it done and quickly. I'm not playing games. All I want is mission accomplished much you take care of business and we go our separate ways. Reporter: And the Michigan wife who wants her husband gone and doesn't care how ugly it gets as long as it's not in the house. It would be messy in the house. Reporter: For the first time ever a group of men hired to kill and on their way to a sit-down exclusively with ABC news. But these men all have a secret. They are undercover federal agents with the ATF posing as hit men. They meet us at ATF headquarters where we have makeup artists waiting. This morning. Reporter: Their appearances completely changed. Prosthetic nose, cheeks, facial hair. We have never seen an entrance quite like this. Show of hands, how many are in a disguise today? Because any of them could be in the middle of a case right now just like this one. Right there on surveillance that's Nicole fasenda, a soccer mom and scorned lover sitting in a parking lot, unsuspecting workers and shoppers pushing their carts right past her. She mes with a hit man. That's what most have on their grocery list plotting revenge on the other woman, the father of her child has a double life, another girlfriend and another family, two children. I played every scenario through my head a million times. Do I want the car to go off the highway. Do I want someone to just come up and take her out. Do I want me to go into the house with my silencer and take them all out. Reporter: Murder for hire in America. On your lunch break. I wouldn't care if she was in a horrible, horrible, horrible car accident and mangled up. Reporter: And she goes further. She wants proof. I want to go to her funeral and spit in the casket. You want her dead. I will be happiest when this woman is dead and buried and six feet under. Reporter: Nicole is now digging her own grave. That is the moment right there when the so-called hit men, the informant tells her the deed is done and her stunning reaction and what's she saying about it all. How does she explain herself tonight as these unbelievable cases unfold on 239, "20/20" on at
This transcript has been automatically generated and may not be 100% accurate.