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Murder Abroad: The Amanda Knox Story

Aired June 4, 2011 - 20:00   ET

THIS IS A RUSH TRANSCRIPT. THIS COPY MAY NOT BE IN ITS FINAL FORM AND MAY BE UPDATED.


DREW GRIFFITH, CNN SPECIAL INVESTIGATIVE UNIT CORRESPONDENT: In Italy a British exchange student raped and murdered in her room.

UNIDENTIFIED MALE: It was horrible. The young lady bled to death.

GRIFFITH: Amanda Knox, her American roommate, is charged with the crime.

EDDA MELLAS, MOTHER: My husband called me and said they've arrested Amanda.

GRIFFITH: A media frenzy.

UNIDENTIFIED FEMALE: Can we just be advised?

GRIFFITH: Ripe with tales of cover-ups and sex games turned deadly all centered around the beautiful young student dubbed "Foxy Knoxy" by the tabloids.

Now Amanda Knox sits in this Italian prison convicted of MURDER ABROAD.

Amanda Knox was going into her junior year of college. Her mother Edda recalls Amanda, the fresh-faced 20-year-old, intent on adventure.

E. MELLAS: She was going to study abroad going into college somewhere. She didn't know where yet.

GRIFFITH: Amanda would decide on Perugia, Italy. Her sister Deanna remembers when she moved into this house which she shared with three other girls, two Italians and one British student named Meredith Kercher.

(On camera): Why was she so set on that apartment?

DEANNA KNOX, SISTER: I think it's because of the people really. It was close to the college and her roommates are the sweetest people in the world.

GRIFFITH (voice-over): But after only six weeks in Italy, on the night of November 1st, 2007, Amanda's overseas adventure would take a bizarre turn. Amanda claims she slept over with her boyfriend Raffaele Sollecito that night. According to her, they cooked dinner at his house, smoked hashish and made love.

On that same night, Meredith Kercher returned to the home she shared with Amanda after watching a movie with friends. Sometime between 11:00 p.m. and midnight a witness living in these apartments across the street claimed to hear a scream and multiple footsteps running away from the house in opposite directions.

The next day Knox says she returned home to shower and change clothes. Then she noticed something was wrong. One roommate's room was turned upside down. A rock on the floor and a broken window. Meredith Kercher's door was locked, and she wasn't answering her cell phone.

E. MELLAS: I got the phone calls about when she came to her house and Amanda kept saying, I've gotten a hold of everybody. I can't get a hold of Meredith. She's not answering her phone. Her door is locked. And you know there was lots of concern.

And I said, OK. You know, call the police, and she then she did, and, you know, the police came, and then they had actually one of the other roommates' boyfriends broke down the door because the police wouldn't do it.

GRIFFITH: Behind Meredith's bedroom door was her body covered by a blanket, blood everywhere. Meredith had been sexually assaulted, stabbed, and slashed in the neck. A bloody handprint left on the wall. Bloody footprints on the floor.

As police began to process the crime scene, suspicion soon began to fall upon Amanda. Partly due to what police believed was a faked forced entry through the window. Observers also thought Amanda's behavior was odd. She and Raffaele stayed in the living room while the others broke into Meredith's room.

Francesco Maresca is an attorney hired by the victim's family. He says Amanda's behavior was enough to make her a suspect.

FRANCESO MARESCA, MEREDITH KERCHER'S ATTORNEY (Through Translator): The famous behavior of Amanda Knox cannot be justifiable if we compare it to the way normal people behave.

GRIFFITH: In this video Amanda and her boyfriend Raffaele comfort each other outside the house. But at the police station witnesses say they laughed and made faces, heightening suspicions about them.

To Amanda Knox and Raffaele Sollecito, the police station would become all too familiar over the coming days. Her father, Curt, recalls the week affect the grisly discovery.

CURT KNOX, FATHER: Between the time that they actually found Meredith and when Amanda was arrested, there was roughly a 90-hour timeframe. And I'm ball parking the numbers there.

During that time, Amanda was in the police station for questioning for -- I believe it was 52 hours.

GRIFFITH: As the days passed, the interrogations became longer and more intense. Without a lawyer, Amanda continued to talk to the police. A decision her mother Edda Mellas regrets to this day. E. MELLAS: You know, would have, could have, should have. I should have insisted that she leave the country. I should have insisted that she not talk to anybody. I should have gotten her a lawyer immediately.

GRIFFITH: Meanwhile, media interests surrounding the crime began to surge. Information was leaked to the press almost daily. Reports stating the victim knew her killer, or even a woman committed the crime, went viral. Soon articles were reporting that Meredith Kercher was the victim of a sex game gone wrong.

C. KNOX: In Italy you could make up a story or you could say you heard it from some guy that was laying in a ditch, and it could be -- you can write the story, and then all of a sudden it goes viral.

GRIFFITH: As the media circus grew, so did the pressure on police to solve the case. On the night of November 5th, the police interrogated Amanda all night and into the next morning. It was during this session Amanda confessed she was at the house that night. Her boss Patrick Lumumba was there as well. At that point Amanda Knox officially ceased to be a witness. She became the suspect.

The police held a press conference later that day announcing to the world they had solved the crime, case closed. According to police, Meredith Kercher had been killed because she would not take part in a sex game, a sex game orchestrated by Amanda Knox, her boyfriend, Raffaele, and Patrick Lumumba.

MARESCA (Through Translator): I've always said that this is a crime that was born of succession. It was step by step. There was no planning.

GRIFFITH: All three were arrested and charged with murder, but the tabloid press turned their attention to one of the accused in particular. Amanda. When the papers hit newsstands the next day, "Foxy Knoxy" would be all over the front page.

In the weeks and months that followed their arrests, new evidence would emerge. A knife found in Raffaele's apartment. Both Amanda's and Meredith's DNA on it. Meredith's bra clasp tested positive for Raffaele's DNA.

A homeless man came forward claiming to have seen the couple near the house on the night of the murder.

E. MELLAS: We kept thinking, oh, this is a big mistake. It will get cleared up, and then it just got really weird with the trial and, you know, it just kept going and going and going.

GRIFFITH: The world was captivated. Two attractive young women. One accused of killing the other.

(On camera): So what really did happen to Meredith Kercher, and is Amanda Knox guilty of murder? For the next hour forget everything you know.

(COMMERCIAL BREAK)

GRIFFITH: With an investigation nearly finished and three people under arrest, the press began to focus on who is Amanda Knox? The picture they painted wasn't very flattering.

D. KNOX: I think some of the biggest problems that have happened with my sister have come from the media. The whole angel face with cold eyes. The whole "Foxy Knoxy" thing.

GRIFFITH: To know the real "Foxy Knoxy," you have to go back to Amanda's hometown. Seattle, Washington.

E. MELLAS: Amanda was born here in Seattle in the summer of 1987, the day before I turned 25. So our birthdays are one day apart.

GRIFFITH: Born into a middle class family, her mother a schoolteacher, her father an accountant, divorced when Amanda and her sister were still very young.

D. KNOX: And so growing up it was I spent the majority of my time with my mom. It was every other weekend that me and Amanda went to our dad's.

GRIFFITH: Always active, Amanda earned her nickname "Foxy Knoxy" at a young age, and not from where you might have thought.

(On camera): And soccer is where she earned that nickname that's --

E. MELLAS: Oh, yes.

GRIFFITH: -- come back to haunt her. "Foxy Knoxy", right?

E. MELLAS: Yes. At the age of 8. You know, the 8-year-olds who don't know anything but call each other all kinds of funny nicknames gave her "Foxy Knoxy."

GRIFFITH (voice-over): She was not a typical teenager. Amanda was driven and focused. Unlike most eighth graders, Amanda wanted an academic challenge. So for high school she chose Seattle Prep. A prestigious private school that her parents could not afford.

C. KNOX: Amanda was scholarshiped out to Seattle Prep, so it's not like she was given a silver spoon or anything by any means.

GRIFFITH: Kris Johnson, an English teacher at Seattle Prep, recalls a girl who was different from her classmates.

KRIS JOHNSON, TEACHER: She was so diligent that she signed up for an extra English class at a time when she could have had a free period. She took an extra class so she stood out.

GRIFFITH: And as for boys.

(On camera): Did she have many serious boyfriends before?

D. KNOX: No. She was definitely a very late bloomer. I don't even remember a boyfriend until college.

GRIFFITH (voice-over): She knew very early on that she wanted to see the world.

E. MELLAS: I think Amanda started talking even in middle school about wanting to travel and to see different places.

GRIFFITH: Amanda would take her love of adventure to the University of Washington where she would major in linguistics. Her friend Andrew Sulliver (ph) describes a woman open to the world.

ANDREW SULLIVER, FRIEND: I think it was her just open personality to, you know, see the good things in people and have always a positive attitude about everybody and everything in the world.

GRIFFITH: In college Amanda knew she wanted to spend a year abroad, but to do that she would have to raise money that her parents did not have.

(On camera): How did she do it?

E. MELLAS: She had to save $10,000. She lived extremely frugally, and I mean spent no money on anything, and then worked several jobs at a time. Numerous jobs at a time. Saved every penny.

GRIFFITH (voice-over): Amanda chose to study in Perugia, Italy, a small town in the center of the country. In the late summer of 2007, Amanda and her sister, Deanna, traveled there to get her settled.

On the very first day in town, Deanna found Amanda a place to live.

D. KNOX: We were walking around, and the first thing Amanda did, of course, was go down to her university. So we walk down there, and she went inside, and I sat outside. And this girl came up and was posting something on the fence right next to where I was sitting. And I looked over, and it said, all I could read because I don't speak Italian, was "apartmento."

GRIFFITH (on camera): And that was the apartment?

D. KNOX: That was it.

GRIFFITH (voice-over): Once settled in Perugia, Amanda seemed to be living her dream.

C. KNOX: The first set of pictures she ever sent me were of the little house that she had found, you know, and I was kind of looking at her going, you have that kind of a view out of your backyard? And I was -- and it was really, you know -- I was very happy for her.

GRIFFITH: And just eight days before Meredith's murder, Amanda met a boy. An Italian student named Raffaele Sollecito.

(On camera): Was she falling in love? Did she sound like a girl falling in love? E. MELLAS: I thought, you know, she sounded like a girl was definitely very infatuated with this young man, who was showing her around. You know, they went over to (INAUDIBLE) -- so yes, there was definitely a big infatuation there. I don't think they had time to fall in love by the time they were arrested.

GRIFFITH (voice-over): Amanda Knox, devoted daughter, student, lover? According to this man, murderer.

(On camera): Is Amanda Knox evil?

(COMMERCIAL BREAK)

GRIFFITH: Almost immediately after police say she confessed to her crime, Amanda Knox recants. She tells her parents she broke under stress. In court she would tell jurors how a police officer struck her from behind, how she was denied water, food, a translator. And how she says under pressure by police she was asked repeatedly to dream up, imagine scenarios for how it could have happened.

In a rare interview the prosecutor of Amanda Knox, Giuliano Mignini, agrees to sit down for an extensive on-camera discussion of the evidence. It was an interview he later appeared to regret.

(On camera): Nobody hit her?

GIULIANO MIGNINI, PROSECUTOR (THROUGH TRANSLATOR): No. Absolutely not.

GRIFFITH: Was she asked to imagine scenarios? So she's lying?

MIGNINI (Through Translator): Absolutely. You either see the person or not. I can't ask a person what he or she imagines. This question would make no sense.

GRIFFITH (voice-over): That's not all that wouldn't make sense because it turns out virtually everything Amanda Knox told her interrogators the night of her so-called confession was a lie.

Amanda Knox in this statement told police she was in the house the night of the murder and saw her boss, nightclub owner Patrick Lumumba, and Meredith Kercher go into Meredith's room, and she heard screams.

Amanda's statement adds, "I am very confused, I imagine what could have happened."

Police apparently didn't bother to check the facts about Lumumba. They immediately arrested Amanda Knox, Raffaele Sollecito and Patrick Lumumba for the murder of Meredith Kercher. Mignini and police announcing to the public case solved.

Giuliano Mignini admitted to us even without evidence he knew almost the moment he arrived and laid eyes on Amanda Knox and Raffaele Sollecito, they were involved in the murder.

(On camera): Prior to the forensic investigation, prior to everything really, your intuition or your detective knowledge led you to Amanda Knox and Raffaele Sollecito?

MIGNINI (Through Translator): After the first few weeks we were convinced because of the behavior of the two people and especially Amanda that they were both involved in a crime.

GRIFFITH (voice-over): But almost immediately after the arrests, Mignini had a problem. The third suspect Patrick Lumumba had an airtight alibi. He was in his crowded bar that night. He could not have been involved.

Then the actual forensic tests came back.

GREG HAMPIKIAN, FORENSIC BIOLOGIST: When I looked at it, I was horrified.

GRIFFITH: Greg Hampikian is a forensic biologist at Boise State University, and director of Idaho's Innocence Project. He also was working with the Knox defense team. He says Italian investigators did a good job processing the crime scene, collected excellent evidence, but clung to shakier evidence that proved their theory.

A classic error, says Hampikian. A prosecutor who trusted his gut feeling instead of the science that at that time was pointing to another suspect.

HAMPIKIAN: They didn't like the way Amanda behaved, whatever that means, and so they wanted to investigate her and Raffaele and her boss. When the DNA is finally processed, it's not any of their suspects. So what do you do? And what would you do? You let them go.

GRIFFITH: As Patrick Lumumba was being released from jail, investigators analyzing the bloody evidence left at the crime scene found an entirely new suspect. His name? Rudy Guede, a known petty criminal from the Ivory Coast who fled to Germany shortly after the murder.

It turns out Guede's handprint made in Meredith Kercher's own blood was found in the victim's room. Guede's DNA found inside the victim's body in her vagina. His DNA on her clothing, on her purse, his feces even found on used toilet paper left near an un-flushed toilet down the hall.

And then something else. Guede didn't even know Raffaele and had only met Amanda few times with neighbors.

C. KNOX: Knowing all of that and when he finally got extradited back to Italy, we thought, you know, thank God this is over.

GRIFFITH: It wasn't. Prosecutor Mignini simply swapped suspects. Amanda Knox, Raffaele Sollecito and now Rudy Guede had come to Meredith Kercher hoping to include her in an orgy. When Kercher refused, they pulled out knives and killed her.

Giuliano Mignini would stick to his instincts despite the forensic evidence. (On camera): You were fixated, according to the defense, on Amanda Knox and Raffaele Sollecito and kept imaging new scenarios that made these two people guilty.

MIGNINI (Through Translator): No, absolutely not. I did what I did because I was convinced given the evidence that had been gathered that they were responsible. I am absolutely convinced.

GRIFFITH (voice-over): Rudy Guede, the African drifter, was quickly convicted and sent to prison, implicating Amanda and Raffaele, after which his sentence was reduced. In 2009 Mignini would bring his case against Amanda Knox and her boyfriend to trial.

(COMMERCIAL BREAK)

HALA GORANI, CNN ANCHOR: I'm Hala Gorani. Here are your headlines this hour.

An unruly passenger caused a security scare today aboard a Continental flight headed Chicago from Houston. The plane landed in St. Louis. A man was removed. Airport officials say the passenger had to be restrained while the plane was in flight after he tried to open an exit door.

A Canadian woman who disappeared seven weeks ago has been found and is doing well in a Nevada hospital. Hunters found Rita Chretian in her van on a remote road in northern Nevada. But there's still no sign of her husband. Her family believes she's been surviving in the van. Authorities say her husband left the van to get help. The couple had been vacationing in Oregon when they disappeared.

Incredible video out of Egypt. A tragic events unfolding there. Coptic Christians say they have been targeted and they are demanding protection after a night of violence that killed at least 12 people and injured more than 230.

Crowds of Christians and Muslims clashed again today throwing rocks and bricks before military police separated them. Officials said the clashes started when rumors spread that a woman, a convert to Islam, was being held in a church against her will.

That is a look at your headlines. We now return to "MURDER ABROAD: THE AMANDA KNOX STORY."

GRIFFITH: One of Italy's most notorious murder trials. The case against Amanda Knox and her boyfriend was getting underway. Basing his case mainly on circumstantial evidence, the prosecutor Giuliano Mignini would begin to present witnesses, one who claims to have seen the couple near the home the night of the murder. Two others would come forward saying they heard a scream.

One of them also hearing footsteps running in different directions, but Mignini now would also present scientific evidence, he said, proves Amanda and Raffaele's gift. Two DNA samples. Raffaele's skin cells on Meredith's bra clasp collected 46 days after police first showed up at the murder. And what one expert called an inconclusive sample of what could have been Meredith's DNA found on a knife collected at Raffaele's apartment. On the handle of the knife Amanda's DNA.

According to Prosecutor Mignini, because the victim had never been to Raffaele's apartment, the knife must be the murder weapon.

But tests for blood on the knife turned up negative. Prosecutors explained it's because the knife had been wiped clean.

Forensic expert Greg Hampikian says finding DNA but no blood makes it highly unlikely the knife was used in a bloody murder. He also says it's surprising the prosecutor was even allowed to admit such a small, unexplainable sample as evidence.

HAMPIKIAN: Would this have made it into a U.S. court? I don't think this would have made it on to a U.S. lab report.

GRIFFITH: What also made it into court was Amanda's so-called confession. In a quirk of Italian law the confession was thrown out of the criminal case against Knox, but jurors heard it anyway as part of a civil case being tried simultaneously.

In court jurors heard Mignini's evidence of guilt, then when they went home each night, they heard the news from a tabloid press gone wild. Sensational headlines about the murder suspect dubbed "Foxy Knoxy" were rampant. Completely fabricated stories of how Amanda Knox engaged in sexual orgies, satanic rituals, how she bought bleach to clean up the crime scene. All of it, according to the prosecutor himself, lies.

With no conclusive evidence their daughter was guilty, the Knox family would enter the courtroom just after midnight on Saturday, December 5th, 2009 believing prosecutors had simply not proved their case.

The jury had deliberated for 13 hours. In a moment that haunts him to this day, Curt Knox heard the verdict in Italian. Guilty.

C. KNOX: These two kids were innocent, and to have them, you know, say guilty, it was just devastating. It was literally devastating. And -- you know, I mean, literally the people that were in the courtroom were kind of like --

GRIFFITH: Doug Preston is a best-selling author who dreams up chilling murder plots in his writing shack on the cold coast of Maine. Eleven years ago he had an idea to write a chilling tale, but in a warmer location.

DOUG PRESTON, AUTHOR: I moved to Italy to write a novel, and we rented a house in the Tuscan Hills just outside of Florence.

GRIFFITH: His research began with trying to learn about the Italian justice system. Teaming up with an old Italian crime reporter named Mario Spezzi, he soon was intrigued about a serial killer Italy had yet to catch.

The "Monster of Florence" who killed eight couples from 1968 to 1985, then vanished.

PRESTON: When you are a novelist, you're just making things up. But this was real.

GRIFFITH: Preston would quickly abandon his work of fiction for the real thing and began to learn how the monster targeted young lovers engaging in sex, mostly in cars in the hills above Florence, killing first the man, then dragging the woman out of the car, mutilating and removing her genitals.

For 17 years always using the same gun, the same knife, killing again and again as police failed to solve the case.

PRESTON: Yes, again and again the police arrested innocent people, interrogated them brutally, thought that they had extracted all kinds of really important confessions from them.

GRIFFITH: Preston says with the suspects in custody, the monster would kill again. Police chased wild theories of a satanic cult. Preston and Spezzi began to write of a lone killer and terrible police work.

PRESTON: The book, you know, to be honest, really criticized their investigation very thoroughly, and it wasn't just criticism. It presented irrefutable evidence that the police were on the wrong track.

GRIFFITH: Before the book could even be released, police focused their attention on the authors. Mario Spezzi's villa was raided, his notes confiscated and the journalist placed under arrest, though later released without charges. Police surmised Spezzi knew so much about the killer, he just might be the killer.

Then Preston's phone range.

PRESTON: I thought it was a joke. And then they said, no, Mr. Preston, this is not a joke. We are coming to get you. This is obligatory. You tell us where you are. That will save everyone a lot of trouble.

GRIFFITH (on camera): Preston would find himself at the door of the prosecutor's office here in Perugia where he thought he'd spend a few minutes answering just a few questions.

PRESTON: I had never understood how brutal, psychologically brutal an interrogation is. You feel absolutely helpless.

GRIFFITH: And the chief interrogator was and is?

PRESTON: Giuliano Mignini, this prosecutor, who is -- let me tell you something, he knows exactly what he is doing.

GRIFFITH (voice-over): Giuliano Mignini was the prosecutor for both the monster and the Amanda Knox cases. Just like during Amanda's interrogation Preston also says he was asked to imagine scenarios of how the crime could have occurred. PRESTON: I was terrified. I thought these people have the power to put me in jail for the rest of my life.

GRIFFITH: Preston says he was questioned for two hours. He left the meeting and wrote everything down including the time he went it and the time he left, which is why Giuliano Mignini's recollection of that meeting with Preston is so puzzling.

MIGNINI (Through Translator): It lasted about 20 minutes. No more than that. And it was the first time I had met Preston around 20 minutes.

GRIFFITH (on camera): I interviewed Doug Preston and that is just not true, according to him. He said the interrogation lasted two hours.

MIGNINI (Through Translator): I don't remember now how long he was interviewed for. I believe it was about 20 minutes. Perhaps half an hour. Perhaps who knows. About an hour. I'd have to look at the statements. However what is certain is that when you make a statement, that person must tell the truth. And I challenge some of the things he said.

GRIFFITH: And let me read to you what he said about it. "I began to sweat. The public minister began repeating the same questions over and over again."

PRESTON: And so I said, wait a minute. And I said, are you -- are you -- do you think I've committed a crime? And that's when Mignini said, yes. We don't think it, we know it. We know you have committed a crime. We have the proof. And you are going to confess to it.

GRIFFITH: It sounds very similar to what Amanda Knox described.

MIGNINI (Through Translator): It is completely different. Because I interrogated Preston, Amanda was interrogated gated by the police. Preston wasn't arrested. Amanda was arrested. The two things are completely different. They have absolutely nothing in common apart from the fact that I was the public prosecutor in both cases.

GRIFFITH (voice-over): Amanda Knox describes to her lawyers the very same techniques. Aggressive questioning, asking to speculate, confronted with so-called evidence of criminal activity that police didn't have.

Fearing he would soon be arrested in 2006 Preston fled Italy and has never returned. But the tables were beginning to turn for the prosecutor as Giuliano Mignini would find himself under investigation.

(COMMERCIAL BREAK)

GRIFFITH: For decades now Italian prosecutors have tried and have failed to catch the Monster of Florence who shot and mutilated eight couples in the Tuscan Hills.

Prosecutor Giuliano Mignini's investigation would also end in failure. His case against journalist Mario Spezzi was completely thrown out, and his theory of a satanic cult and massive cover-up in the monster case was being ridiculed by other Italian justices.

And Mignini's tactics, including the wiretapping of offices, became part of a new case. Mignini himself was accused, convicted, and sentenced to a 16-month suspended sentence for abusing his office.

Mignini, who is appealing the conviction, explained to us it's nothing.

MIGNINI (Through Translator): I have seen this many times. When they say convicted of abuse of office, it does not mean abuse of power. Abuse of office is a minor crime in Italy. I mean, it wasn't corruption, just to be clear.

GRIFFITH: But for this proud judicial official of Perugia, the public humiliation was humbling. It was during this very time when Giuliano Mignini was facing embarrassing charges of abusing his office he arrived at the crime scene of Meredith Kercher's murder. His investigation into Kercher's death would not wait for the forensic evidence to be processed. He already had his suspicions.

Within days he announced the horrific crime was solved.

GRIFFITH (on camera): Dr. Mignini, is it possible that a prosecutor who was facing his own troubles perhaps rushed to judgment to solve a sensational crime?

MIGNINI (Through Translator): I did not take any opportunity because that day I just happened to be on duty. A tour of duty of a week. So I did not take an opportunity.

GRIFFITH (voice-over): The morning after our interview with Giuliano Mignini, the prosecutor spots our camera, walks towards me, and off- camera asks what I thought of the interview the night before. If I thought he was being truthful.

Clearly, Mignini is now concerned. His case against Amanda Knox appears to be falling apart.

The tabloid press, still enamored with "Foxy Knoxy," is beginning to tell a different story. Amanda and Raffaele have appealed their conviction. The appeal trial is now underway, and a new judge and new jury have been seated.

Knox, rarely smiles now. Raffaele Sollecito has shaved his head. They have both been imprisoned for more than three years. Knox's family says the couple who had met just eight days before the murder haven't communicated since their arrests.

Before the judge enters, Knox's mouths to Raffaele, are you OK? It is a tender moment in what would be a strange hearing. This morning Amanda Knox's attorneys are to cross-examine an old witness.

He is the homeless man who lived in this park and originally told the court he saw Amanda and Raffaele near the crime scene the night of the murder. Before testimony begins, cameras are ushered out of the court, and police bring in a star prosecution witness that the jury would find laughable.

The homeless heroin addict could no longer remember the exact night he saw the couple. He was confused. It could have been Halloween. Actually, the night before the murder. And then the star witness dropped a bombshell. Admitting he was under investigation by Mignini's office for heroin dealing at the exact moment he became one of Mignini's star witnesses.

In our interview the night before Giuliano Mignini told us he had no doubts, the tramp, as he calls him, was telling the truth.

MIGNINI (Through Translator): If he says he saw them and states it under oath, then we have to believe him unless given reason not to. It's not as if the crime had been filmed. I wish it had been.

GRIFFITH (on camera): Was he offering his testimony in hopes of getting a favor in court?

MIGNINI (Through Translator): No. He didn't get any favor at all. The witness presented himself and gave a statement. That's all. We took his statement because the evidence was relevant.

GRIFFITH: So you believe the testimony of a homeless heroin dealer?

MIGNINI (Through Translator): I don't want to comment on the judicial proceedings regarding this individual. Because he was tried for another matter, something completely different that had nothing to do with this and so for this trial he is a witness.

GRIFFITH (voice-over): With Mignini's main witness now being challenged, it leaves only the scant DNA evidence. And that, too, is about to be challenged.

(COMMERCIAL BREAK)

GRIFFITH: With the prosecution's main witness again being challenged on appeal, the case against Amanda Knox and Raffaele Sollecito seems to be hanging on two very small pieces of DNA evidence.

CNN has learned a court-ordered retesting of the forensic evidence will find no evidence of human blood anywhere on the knife found in Raffaele's apartment. A forensic expert telling CNN the lack of blood makes it's highly unlikely it could have been used in Meredith Kercher's bloody murder.

In addition the tiny spot of what the prosecutors said was Meredith Kercher's DNA on that knife, according to experts, is so small it's not only inconclusive there's there's nothing left to retest.

As for Raffaele Sollecito's DNA found on one spot on Meredith Kercher's metal bra clasp, Prosecutor Giuliano Mignini told us that no additional DNA could be retested because the clasp was ruined in police storage.

MIGNINI (Through Translator): The material from the hook had, I believe, deteriorated due to the presence of rust. And rust cannot be avoided because if you use some antirust product, you destroy any genetic material that is left.

I don't want to go into this. But the material that was taken 3 1/2 years ago was definitive.

GRIFFITH: DNA expert Greg Hampikian says even if the DNA was preserved, it doesn't explain how a single sample of Raffaele's DNA is was all that was found in a bloody and violent crime scene.

HAMPIKIAN: If that's all there is, and from what I've seen, that's all there is, then it's a very weak piece of evidence and it's inconsistent with every other piece of evidence in the case.

GRIFFITH: Twice a week, Amanda's stepfather, Chris Mellas, makes the drive to the prison where his 23-year-old stepdaughter is being held. He works in computer software and was able to move to Italy. So Amanda would always have at least one member of the family here.

CHRIS MELLAS, STEPFATHER: It's about a half hour outside of Perugia.

GRIFFITH: He is hoping this summer he and Amanda will move back home to Seattle, but despite the evidence, or lack of evidence, being presented in the appeal, neither one appears to be hopeful.

(On camera): And how is she holding up? I heard you saying she doesn't want to be too hopeful, but --

C. E. MELLAS: No, she doesn't want to be too hopeful because it's difficult. Things have gone our way in the past and we have been completely kicked in the teeth, so you don't want to -- you don't want to get hopeful.

GRIFFITH (voice-over): Amanda Knox is not allowed to talk to the press. Her stepfather says she has no idea just how big this case has become.

Giuliano Mignini knows all too well. The prosecutor who repeatedly told us he has nothing to be nervous about is again on the defensive. Already found guilty of abuse of his office in the Monster of Florence case, he is now being accused of harassing journalists who criticize his investigation against Amanda Knox.

Last month, the International Committee to Protect Journalists sent a scathing letter to the president of Italy, complaining about Mignini's tactics, in part saying, "It is unacceptable journalists, bloggers, and writers on both sides of the Atlantic should censor themselves by staying away from subjects of public interests such as the Meredith Kercher murder case and Monster of Florence killing because of Prosecutor Mignini's inability to tolerate the scrutiny that comes with public office."

GRIFFITH (on camera): Do you have any doubt, any doubt in your mind that you convicted the wrong people, that Amanda Knox and Raffaele may, indeed, be innocent?

MIGNINI (Through Translator): Listen, I am very sincere so if I made certain requests it was because I was absolutely sure they were responsible, otherwise if I had had any doubt, I would have asked for an acquittal for lack of evidence.

GRIFFITH (voice-over): Mignini is clearly under the gun and needs to make sure his convictions of Amanda Knox and Raffaele Sollecito are upheld on appeal. Exactly why Knox's family is cautious.

E. MELLAS: Sometimes I'm just filled with hope and I know for sure that this is going away. And -- but I was like that during the first trial because there was no evidence.

GRIFFITH: For the Knox family, their entire lives have been put on hold. Curt Knox and his ex-wife Edda have mortgaged everything they own to pay for their daughter's defense.

Curt has two young daughters of his own, Amanda's stepsisters, who have grown up watching their father travel back and forth to Italy. He hopes very soon the trips will end and his entire family will be back together.

C. KNOX: You know, family events and stuff like that, there's always a chair open.

GRIFFITH (on camera): Really?

C. KNOX: Yes. They -- the three girls had their picture taken. The three girls had their picture taken holding a picture of Amanda.