Reporter: It's almost curtains for Nicole faccenda's murder-for-hire drama. Her plot to kill her ex-boyfriend's new lover -- fatally flawed, and about to flop. Ho you doing? Have a seat. Reporter: The... See More
Reporter: It's almost curtains for Nicole faccenda's murder-for-hire drama. Her plot to kill her ex-boyfriend's new lover -- fatally flawed, and about to flop. Ho you doing? Have a seat. Reporter: The hit man hired by the New Jersey soccer mom is a cop. His sidekick is a snitch. The ATF is watching every move, building their murder-for-hire case. The would-be victim, Jennifer, now part of the case, getting ready to play dead. But Nicole knows none of this. She thinks everything is running according to plan. Nicole, so eager now. She doubles the fee -- putting a $20,000 price on Jennifer's head. And look at this -- the photo she texted to sonny and Jose, making sure they don't kill the wrong woman. And then she texts the picture of the girlfriend. Yeah, it doesn't get any more serious than that. Reporter: Tonight, right here for the first time, we hear the flurry of phone calls that follow those parking lot meetings. Sometimes Nicole, the soccer mom, calling from the sidelines, a few feet away from where her child is playing. I'm at a soccer game, and my sister is here too with her kids so when she walks over, I hang up. Reporter: The hit men wonder, once their deed is done, when Jennifer is supposedly dead, how to prove it to Nicole? When she's finished and gone -- how can I show you she's gone? I don't know. You got to figure that out. I have no idea. Picture? No idea. Picture. That's the only way. I can get him to give you a picture of her dead, finished. You figure out how to give me proof. The only proof I have is, when I go to the funeral, I'm gonna be happy as . Reporter: Their solution, a gruesome souvenir, a photo of her dead. But Nicole has a better idea. I don't want a picture. We're gonna get busted with a picture. I don't want any pictures. I'm gonna go to the funeral. Reporter: She doesn't want a picture? She wants to go to the funeral. Reporter: She wants to go to the funeral? She wants that satisfaction knowing what she's done and kind of savor it, which is quite sick. Reporter: So seeing the casket, she thinks it's better proof than any picture? Absolutely. At the end of the rainbow, when it's all done and finished, you'll pay him the rest. Correct? At the end of the rainbow, you know, we'll figure it out. Absolutely. When you see a bullet in her head, finished, will you have the money ready for him? Bottom line. Yeah, I will. When it's done. Reporter: Nicole is now one step away from closing the deal. She'll make a down payment, the balance due after Jennifer is dead. Murder on layaway. They set up another meet at a local restaurant. But she has no idea those ATF agents will be there, too. You're right here at the Olive Garden. People are having dinner, and you're waiting for her to show up with the cash. Right. Reporter: And you're waiting and you're waiting and she's not here. And no sign of her. No sign of her. Reporter: Concerns racing through their heads. Has she changed her mind? Does she now want out of that lifetime movie? Or worse -- has she taken action on her own? Suddenly, she's calling sonny. Hey, where are you? Reporter: And where has she been all this time? At her son's soccer game. And she's now pulling up right next door. And where is she? She's over at the Exxon. Reporter: Over here. She's now just a few hundred feet away. Okay, he's moving. He's going to go now. Reporter: The agents scramble, their wires, their cameras, out of position. Listen, he's gonna have to walk over to the Exxon station. Reporter: They see Nicole hand sonny a thick envelope. And what's inside? Her down payment. Cash. Reporter: How much cash? $2,000. Reporter: Basically, it's a down payment on murder. It's a down payment on murder. Once this money was received, we knew at any point that we could, in fact, arrest her. Reporter: The agents have heard enough, but still no arrest. Nicole, allowed to just drive off. They want more evidence. For an air-tight case. As the murder-for-hire plot enters its final hours. The next call I'm going to do is when she's gone. She's 86. Dead. Finito. Once you're dead, you're dead. You follow where I'm going with this? Yeah. Reporter: Nicole is at work at a New Jersey hotel, getting the phone call she says she'd been waiting for. The hit on the other woman. Sonny, the hitman's helper, is on the line, calling to say the job is done. Listen to me, listen to me clearly. He did what you said to do. Jennifer is dead. No way. Jennifer is dead. He shot her. He said he shot her in the head. She's done. She's dead. Reporter: Sonny tells Nicole the hitman made the murder look like a botched robbery. You said to get rid of somebody. He shot her. Made it look like a robbery. He wants his Money. He's going to go to your hotel and get it from you. I don't care, he can come here. It's not here, and I don't have anything here. Reporter: Nicole doesn't seem to believe it. He did what you said to do. He killed her. He wants the Money. Okay, you got to calm down. You have to calm the hell down first of all. Reporter: ATF agent Mike Alongi and his team still tracking the case, watching and listening to it all. She didn't believe the murder hadn't been completed. Because she was making phone calls and actually watching on television to see if a murder had been committed. Reporter: Nicole will see if she can fit paying off the hitman into her busy schedule. I'm at work since before 10:00. I have to go to two more appointments. I can't even be bothered in these two appointments. I will call you when I'm done with these two appointments. I got a 12:00 and a 1:00, and then I will call you after that. Reporter: Nicole, at work, not knowing she's enjoying her final moments of freedom. The ATF agents send in sonny, the informant, still playing the part of the killer's helper to see what Nicole will do, what she'll say. I can't believe you did this to me. Don't show up here. That's not cool. Don't believe either one of you. At this point, I don't believe either one of you. Reporter: But Nicole's day is about to get much worse. She's working here, at a restaurant. Yes. She's a catering manager. Reporter: And she had no idea that you're about to move in. No, no clue. Reporter: So you come around the front here. And and you walk right into the restaurant? Yeah, we walked right into the doubletree. Reporter: And you asked for her? And we just asked for her at the front reception desk. Reporter: And she comes out? And she comes out and she was just questioning and looked, you know, surprised and startled. Reporter: And what do you tell her? That she was being placed under arrest. Reporter: So you cuff her. You pull her right out of these doors here? Yes. Reporter: And what was she saying in the car? She was like, "I can't believe this is happening." And she was starting to get teary. And she was like, "Why, why, why?" Reporter: She actually had some tears in the car? Oh yeah. In the back seat? Yes. Reporter: Not a killer after all. Just a grim weeper. Were those tears for the girlfriend she tried to have killed? No, they were for herself. Reporter: You'll remember our hitmen who are, in fact, undercover federal agents. When you're in that courtroom, and you see the person that you caught, and they look at you, what do you read in their eyes? They hate you. That person trusted you with everything and suddenly, they find out that you have betrayed them. I enjoy that part. That's the part where they know they've been had. It's the only time you can come out and say, yeah, I got you. Reporter: Nicole eventually pleading guilty, getting ten years in federal prison. And from that prison in West Virginia, she is reaching out to "20/20," sending an e-mail saying, "I thank god every day that no one got hurt from my careless actions. I would like to apologize to the victim and her family. I am not, and have never been, a violent person. I was a woman destroyed by emotions and I am paying for it dearly." Nicole also accuses the feds of baiting her. "I was at an emotional low point in my life and they took advantage of that," she says. But that hitman, reminding us in that supermarket parking lot, he gave her several outs. I want to make sure that you know what you're getting yourself into when you want this done because, like I said, there's no turning back. Reporter: When we come back, the reason Jennifer is afraid it'll never be "Done." Why she fears Nicole, even from behind bars, is still a threat. Because you think she's still determined. Yes. I do. Reporter: And an emotional moment in that supermarket parking lot where that plot began. See who Jennifer is about to
This transcript has been automatically generated and may not be 100% accurate.