"When Amanda Knox gets out, if she needs a roommate, I'll send my daughter over," retired FBI Special Agent Steve Moore told "Good Morning America." "The evidence is completely conclusive."
Moore, a 25-year FBI veteran who investigated murders around the world before retiring two years ago, has independently researched and analyzed her case for the past year while Knox waited for her appeal.
Knox, 22, has spent nearly three years in an Italian prison since her November 2007 arrest for the murder of her British roommate, Meredith Kercher. Kercher was found sexually assaulted and her throat slashed, her half naked body under a duvet in her bedroom.
Knox and her former Italian boyfriend Raffaele Sollecito were convicted of murder last December after a nearly a year long trial. A third person, Ivory Coast drifter Rudy Guede, whose DNA was found at the crime scene ,was convicted of taking part in the homicide in an earlier trial.
At first, Moore said, he firmly believed Knox was guilty as charged.
"The police said she is. She was arrested," he said. "It just seemed that's the way it was."
Moore, who has never spoken to Knox's family or lawyers, said it was his wife who urged him to look into Knox's case, convinced she was innocent. In November, Moore obtained the crime scene video, autopsy photos and legal documents. He spent weeks poring through them.
His opinion, he said, quickly changed.
"I couldn't figure out why Amanda and Raffaele weren't eliminated on day one as suspects," he said. "I kept thinking the smoking gun would pop up -- and it didn't come. I didn't know why they were in jail."
Initially, Knox said she was at her boyfriend's house the night of the murder. She was arrested days later after an overnight interrogation in which she said she had a vision she was in the kitchen of the cottage she shared with Kercher the night of the murder and heard screams. She has claimed that she became confused and scared because she was bullied, even struck by her interrogators, and recanted the remarks soon after.
The investigation found none of Knox's DNA -- no hair, blood or fingerprints -- in the bedroom where Kercher was murdered.
Prosecutors allege that the murder weapon is a knife found at Sollecito's apartment with Knox's DNA on the handle and Kercher's on the blade.
Moore dismissed the knife evidence, pointing out that Knox often used it to cook. He also said Italian prosecutors were grasping at straws by pointing to what they say is evidence that Knox tried to wash off Kercher's blood in her own bathroom.
"There is no DNA evidence. What they're saying is that whoever killed Meredith cleaned up in Amanda's bathroom. That's all they say," Moore said. "They found Amanda's DNA in her own bathroom? Astounding."
Amanda Knox Awaits Appeal, Hopes for Freedom
Moore said he spent hours watching video of Italian police officials combing through the crime scene and was shocked at what he saw.
"They were doing unsound forensic techniques that lead to cross contamination. Their techniques were horrible," he said. "If you showed that video tape in American court you would have lost more of your evidence."
He also slammed Italian authorities for their initial interrogation of Knox, which he likened to tactics used by "third-world intelligence agencies."
He pointed to her being questioned for hours, from about 10 p.m. to 6 a.m. when she was exhausted.
"No food, no coffee, no bathroom breaks -- nothing," Moore said, adding that she was interrogated in Italian, which Knox did not speak fluently at the time. "She gave them a confused indictment of someone else … which she recanted after she got some food."
Knox's appeal is tentatively scheduled to begin Nov. 24. A new panel of two judges and six jurors from Perugia will reexamine Knox's case. A decision is expected by March.
Moore said he has no reason to believe he would be allowed to testify at the appeal or that Italian courts would be interested in anything an American had to say in her defense. But he's hoping Italian forensic experts convinced of Knox's evidence will pick up where he left off.
"The final court of appeal is going to be the press, the public," Moore said, charging that the public knows very little about how questionable the evidence against Knox really is.
In March, prosecutors filed an appeal seeking an even harsher sentence for Knox, who was ordered to serve 26 years in prison. The prosecutor is asking that she be sentenced to a life term. Knox's lawyers responded with an appeal in March, which asked for her conviction to be overturned.
Knox's appeal also called for an independent review of the DNA evidence, a request denied by a judge during her trial.
Knox's Third Birthday in Prison Marked By Singing, Crab Cakes
Knox has celebrated three birthdays, missed her college graduation and cut short her famous long locks while in prison. She passes time playing guitar at the prison mass, studying Italian and German and exercising during the one hour she can leave her cell.
"Amanda and I have now spent, her birthday and mine are a day apart, so we've spent the last three birthdays together," Knox's mother, Edda Mellas, told "Good Morning America." "We sing happy birthday for her. This year she got a lot of people. The guards and other inmates were singing to her."
But Mellas said the waiting is taking a toll on her daughter.
"The summer was hard, it's so hot [in the prison]. We tend to talk a lot about what she's doing to cope, but being locked up for a crime you didn't commit is devastating, it's almost unbearable, and she's having a tough time. But you know she's doing what she needs to do," she said.
Italian parliamentarian, Ricco Girlanda, who has said he is trying to soothe the diplomatic tensions that erupted during Knox's case, has visited Amanda in prison.
In more than 20 jailhouse conversations, Girland says Knox told him she one day hopes to adopt children and work as a writer. While Girlanda has not weighed in on Knox's guilt or innocence, he has penned a book about Knox to be released in October.