Brooklyn man found guilty in 2003 killing of student after house party: Part 1

Though John Giuca has maintained his innocence, he was found guilty of the murder of 19-year-old Mark Fisher after a house party Giuca hosted in 2003.
7:02 | 05/18/19

Coming up in the next {{countdown}} {{countdownlbl}}

Coming up next:

{{nextVideo.title}}

{{nextVideo.description}}

Skip to this video now

Now Playing:

{{currentVideo.title}}

Comments
Related Extras
Related Videos
Video Transcript
Transcript for Brooklyn man found guilty in 2003 killing of student after house party: Part 1
Reporter: They say nothing is as powerful as a mother's love. For Dorine Juliano, that was true. I'm John's voice. Reporter: This is the story of one mom's quest to try to prove her son's innocence ach he's convicted of a heinous murderer and the lengths she would go to, to set him free. I was going to look like a you don't let your children down. You fight for your children. Reporter: It started in Brooklyn in 2003, when 19-year-old mark fisher turned up dead. Tonight police are trying to figure out who murdered a 19-year-old college student. His body was found dumped. On the streets of Brooklyn new York. He was young. He was tall. He was an up and coming football player at his university, and he came to the city for fun. He just wanted to have a good and he ends up dead in Brooklyn. Reporter: Earlier that night, he was out with college friends, bar hopping in New York City. As the night wears on, mark heads to an after party in Brooklyn at the house of John juca, someone mark had just met that night. Tell me your impression of mark fisher. He had a personality that was likeable. Reporter: Was he intoxicated? Yeah, he was drunk. Reporter: Were you? Yes. These kids are sitting around, drinking, smoking weed, and Antonio Russo, a neighborhood kid kind of known to cops in the area. Came to the party. Was there anything between Antonio Russo and mark fisher that night? Not that I saw. Reporter: At sun begins to rise, mark is asked to leave the house party. He leaves the house, and he's next seen dead. Reporter: Mark's body was found two blocks away from John juca's house. I cried and I just say why? It doesn't mak sense to me. Why would somebody do this to him? He was such a good person. Reporter: Just about an hour before he died he went to a convenience store and took out cash, just $20 at 5:25 A.M. And then walks back to the party. But the key detail is who goes on the atm run with him, Antonio Russo. The wallet was missing from mark fisher's body. So that created the suspicion that it was a robbery. The 19-year-old's body was found wrapped in a blanket at the end of a driveway there at that home, Argyle rode. The blanket found with the body came from the juca home. That become as critical starting point for investigators. You got a call. I got a call from John. Reporter: What did he say? He said ma, you need to come home. And I said is everything okay? And he said you need to come home. Reporter: And so you get home, frantic. What's the scene here? The press was on my lawn. Reporter: Already? Yeah. And detectives were on my porch. Reporter: But detectives aren't only closing in on John, they're looking at Antonio Russo, too. So there's a whole lot of smoke around Antonio Russo and John juca, but nothing that directly, forensically ties them to the crime scene, no DNA, no fingerprints. Reporter: Nearly a year goes by with no arrests. But then? Now, eyewitness news at 5:00. A college football star found dead more than a year without an arrest. Now police say they've captured his killer. Have you got the right guy? Any comment, Anthony? They say you killed him for $20, Antonio. In 2004, 13 months after the murder, Antonio Russo was arrested. One of Russo's first comments after he's arrested is, are you go being to arrest the others as well? And they say who do you mean? He goes oh, no, no, no, never mind. One month later in December, while he's returning from Christmas shopping, John juca's arrested as well. Reporter: Did you give Antonio Russo the gun that No. Reporter: Did you put him up to it? No. Reporter: Did you have anything to do with the murder of mark fisher? No. Reporter: So you believe the police arrested the wrong man. I know it. Fast forward to 2005. John juca and Antonio Russo are on trial for this homicide. Reporter: You sat in the courtroom every day. Yes. Reporter: Was there any forensic evidence linking your son to the murder? Zero. Zero. This case was on testimony only. He said-she said. Testimony only. You had his long-time friend, one of his best friends, testifying against him. Al Cleary got up on the witness stand and said you had a .22 pistol, the same caliber at murder weapon. Yes. Reporter: And he also said you told him to show mark what's up. That's so ridiculous. That's not in my vocabulary. As the trial went on, here comes this special witness. John aveto. Reporter: This jailhouse informant says John juca confesses to pistol whipping mark fisher and somebody else grabs the gun and shoots him. So it putting John juca right on the scene of the crime. Reporter: And when he got up on the stand and said you confessed to him. I was so totally shocked. What I thought the jury would easily be able to see through it. After the prosecution made its case, it was then the turn of the defense. But, as it turned out, neither the defense for Mr. Juca nor for Mr. Russo opted to call anyone to the stand. They rested their case. That was that. It's only an hour and a half later, and the jury comes back in and says guilty as charged. And John juca's taken out in handcuffs. It was torment. I turned white like a ghost, and I could not believe it. It was like my brain wouldn't even accept it. Reporter: John is found guilty of felony murder and sentenced to 25 years to life in prison. I'm devastated. That doesn't mean I'm going to give up. I'm never going to give up. John is innocent. And she's already starting to think, how can I fix this? And she's not going to stop thinking of that until she comes up with a plan. When there's an injustice, fight. Tremfya is for adults with moderate

This transcript has been automatically generated and may not be 100% accurate.

{"duration":"7:02","description":"Though John Giuca has maintained his innocence, he was found guilty of the murder of 19-year-old Mark Fisher after a house party Giuca hosted in 2003.","mediaType":"default","section":"ABCNews/Nightline","id":"63120550","title":"Brooklyn man found guilty in 2003 killing of student after house party: Part 1","url":"/Nightline/video/brooklyn-man-found-guilty-2003-killing-student-house-63120550"}