A convicted child murderer testified Saturday at the appeals trial of Amanda Knox, saying that a fellow inmate had told him the American student had nothing to do with the killing of her roommate in Italy.

Mario Alessi, who is serving a life sentence for one of Italy's most shocking crimes, the kidnap-murder of an Italian toddler snatched from his home, was called by defense lawyers as a witness.
He was one of five witnesses heard Saturday, also including a police informant who testified from behind a cover and a Neapolitan mobster with a flamboyant attitude.

Knox was convicted of sexually assaulting and murdering British student Meredith Kercher in the house the two shared in Perugia, and sentenced to 26 years in prison. Her co-defendant and ex-boyfriend, Raffaele Sollecito of Italy, was also convicted and sentenced to 25 years. Knox and Sollecito, who both attended Saturday's session, deny wrongdoing and are appealing their convictions.

Rudy Hermann Guede, an Ivorian, was convicted in a separate proceeding. His conviction has been confirmed by Italy's highest criminal court. Guede also denies wrongdoing, but admitted being in Knox's and Kercher's apartment the night of the murder on Nov. 1, 2007.

Alessi is being held in the same prison as Guede. He testified that the Ivorian told him that Knox and Sollecito are innocent, speaking in prison conversations in November 2009. That was about a month before Knox and Sollecito were convicted in the first trial and while Guede had already been convicted and was appealing.

Alessi said Guede approached him during recreation time at the Viterbo prison. "Rudy links arms with me, inviting me to take a walk with him, he has something important to tell me," Alessi testified. He quoted Guede as saying he was worried because "I don't know whether to tell the truth or not," and that the truth "is altogether different from what you hear on TV."

Alessi was called to testify by Sollecito's defense.

Guede has denied speaking to Alessi about the case, and he will be heard at the next hearing on June 27 as a witness for the prosecution to counter Alessi's claim. Guede is currently serving a 16-year prison sentence.

According to Alessi, Guede said he and a friend went over to the house with the intent of having three-way sex with Kercher, who was 21. When she refused, the scene turned violent. Alessi said Guede told him he had gone to the bathroom and upon coming back he had seen his friend holding Kercher to the ground.

Eventually, "a knife appeared, almost out of nowhere," Alessi said, quoting Guede as saying that it was pointed at Kercher's throat. As she was fighting, she got her throat slit, Alessi claimed. Guede tried to rescue her, Alessi said, but his friend stopped him, saying "We've got to finish her, otherwise we'll rot in jail."

Guede did not reveal the identity of his alleged accomplice, according to the witness. Alessi said he and Guede had developed a friendship in prison but eventually Alessi broke it off as he realized that Guede "said two innocent people were in jail" but did nothing about it. Alessi then contacted the lawyers representing Sollecito.

Alessi, a bricklayer, was convicted of the murder of the murder of 18-month-old Tommaso Onofri several years ago.

Francesco Maresca, a lawyer for the Kercher family, tried to cast doubt on Alessi's credibility, recounting his criminal record, then showing a picture of Onofri and asking Alessi if he knew him. "We do," Maresca said, when Alessi muttered "No."

Three more witnesses were called to back up Alessi's testimony, including police informant Marco Castelluccio, who took the stand behind a blue cover, guards around him.

They mostly said they had heard the story in prison chatter from Alessi and for the most part confirmed his version.

The fifth witness, Luciano Aviello, told a completely different story, saying that his brother and an accomplice had killed Kercher.

Aviello, a mobster who has been convicted of several crimes including defamation, was called up by Knox's defense team to raise doubt on her involvement. He said he was at his home in Perugia the night of the murder when his brother showed up, his jacket ripped and his arm bleeding. "He was very emotional," Aviello said of his brother. "I took care of his wounds, and tried to calm him down."

Aviello said his brother, currently a fugitive from justice, was on a "job" robbing a house with an Albanian friend. They got the wrong address and found themselves in the house where Kercher and Knox lived, finding the Briton alone. They started sexually attacking her and then killed her, according to Aviello's version.

Speaking in a thick Neapolitan accent and gesticulating profusely, Aviello at one point was so agitated he had to be calmed down by police standing guard next to him.

"Aviello was funny," Knox's stepfather Chris Mellas said. "Today was one of the most bizarre hearings."

Mellas said Alessi's testimony was straightforward, and that "the fact that multiple people are corroborating the story lends a certain degree of credence to it."

Maresca, the lawyer representing the Kerchers, disagreed, saying the hearing today was a "farce."

"We heard from people serving life sentences, convicts, proven liars," Maresca said. "Aviello has been convicted repeatedly for defamation."

"Alessi is totally unreliable. Just how he invented the story we heard today, he made it up for his fellow inmates."

Much of the appeals trial hinges on a review of DNA evidence. The court-ordered review is being carried out by two independent experts and will be concluded by the end of the month.