Transcript for Some witnesses at John Giuca's murder trial later recant testimony: Part 9
The undercover mom got a huge media play. Everyone was talking about what lengths would any mother go to. The real question was, did she have the goods? Was she going to be able to successfully get her son a get out of jail card? The first stop with these bombshell audio tapes is back to judge Maris who had been the trial judge. John giuca's attorneys, they file a motion to vacate the conviction and get him a new trial. On the grounds that there was juror misconduct. I think that Doreen assumed he was going to immediately order a new trial. Judge Allen Maris, he didn't even hold a hearing. After we submitted the motion and all the recordings, he didn't even hold a hearing. It's a whimper, not a bang. There's no big courtroom drama moment. He just denies the motion. So the judge denies the defense motion for two reasons. One, the judge was saying it doesn't show that the juror intentionally lied in the jury selection process. And secondly, that the tape isn't necessarily reliable. He says, "There's no way to prove that they weren't altered. And he scolds her for being a vigilante who's gone off on her own and tried to do the job of law enforcement. I mean, is it fair to say they laughed you out of court? Laughed me out of court. If anything, they were afraid of the truth. Their easy way out is just call Doreen crazy. He said that you were guilty of extraordinary misconduct. Did you go too far? Maybe it was misguided, but definitely not too far. Because any mother would do it. Even after being lambasted by the judge, she did not give up. She will never give up. Just give me my son! I just went nuts. I know that the evidence is there. Because the verdict was wrong. So I decided to investigate each and every person who wrongfully testified against my son. As she's toiling over this case, literally pouring over court records, two of the key witnesses are about to come forward and turn this case on its head. Lauren Calciano, who was giuca's former girlfriend, comes forward to recant her testimony. For years, I have thought and regretted the testimony. I felt compelled to set the record straight. She signs a sworn affidavit saying what she testified to was a lie. Sworn affidavit, meaning I promise I'm not lying and you can charge me with perjury if I am. Lauren Calciano testified at the trial that giuca had confided in her that he had given Anthony Russo a gun to rob the victim, mark fisher. She claimed that prosecutors and investigators were subtly or not so subtly threatening to make her father's life more difficult because he was serving time. Nicolazzi and detectives told me that they were aware that my father was in prison and that by not cooperating with them I was "Going to make this hard on him and my family." I cried when I finally found out she was actually finally telling the truth. I said to myself, "There is a god." Because for years I know that she was pressured to say these things and lie. So that's huge. And yet, Doreen set her sights on the star witness, the prosecution's jailhouse informant. So if you remember, back at the first trial, John avitto was this mysterious witness that come forward, jailhouse snitch. And allegedly, for some reason, John giuca felt the need to confide in John avitto about what happened that night. This avitto was basically putting the target right on John giuca's head. Doreen sets out to try to unover why, in her view, John avitto lied on the stand. This time she turns to a pro. She hires a private investigator. So, Jay salpeter is your classic, grizzled, veteran private eye, and he's one of those guys who believes in truth, justice, and the American way. What did they ask you to do? Well, they wanted me to try and interview him. Now it's many years later, let's see who John is now. Maybe he wants to tell the truth, or he was telling the truth, I didn't know. I contacted John avitto and I asked to meet with him. I told John, "I'm a retired New York detective and I'm a private investigator and I'm working the John giuca case." He was a little apprehensive. And how does a investigator like you move forward on getting somebody to trust you? I like to start with, you get more with sugar than spice. So Jay salpeter convinced John avido to meet him in his car and had a tape recorder rolling. Okay, I'm here regarding John giuca. Could you tell me how you got involved in this case? Well, I was in Riker's island, and me and John became good friends. So, the first time, avitto says, "Oh, no, this is basically what happened," and repeats his courtroom testimony. He did tell me he hit the guy on the head with the gun, the kid went down, he start kickin' and punchin'. He did tell me all that. He's sticking by his jailhouse confession. Right, but I'm not ready to start a confrontation with him. Just keep it going, let him speak, and as a detective, you learn when you let people speak, things come out. It's an exercise in private investigating 101 because he goes after this target, John avitto, slowly and methodically. And after multiple meetings, he gets him to clear his I don't know, what else do you want me to say? I just want the truth, that's all. The whole thing was a lie. The whole thing was a lie? Yeah. He is now coming forward and saying that he made up the story about giuca's confession. And he was the most important witness in the case. Jay salpeter got John avitto to admit that he had been in a court mandated drug program. I had gotten into violations of the program and stuff. Which should have put him in jail. But according to avitto he had some sort of deal with the prosecutors. And they helped me get out of those. Right. Just to keep me so I can testify. And you knew that you were supposed to put you in jail, right? Right. So now, he's coming forward and saying, "I made it up." I made it up because I was cut a deal." If it's true that nicolazzi basically made promises to this critical witness and then didn't disclose it, that's a grave legal sin. And it's that potential grave legal sin that will that will put anna-sigga nicolazzi in the hot seat. I've been prosecuting murders for 15 years and I've never lost a case. She comes out and she says, "You know, I've never lost a case."' Oh, god. You know why? 'Cause she's a cheater. Nobody ever wins all the time. Arm out,
This transcript has been automatically generated and may not be 100% accurate.