Meredith Kercher's father has appealed to her murderer to finally "come clean" and reveal what really happened the night she was stabbed to death.
Rudy Guede is the only person who remains behind bars in Italy for sexually assaulting and killing the British student and has "nothing to lose" from telling the truth now, John Kercher argued.
Amanda Knox, from Seattle, US, and her Italian ex-boyfriend Raffaele Sollecito walked free from prison in Perugia last October when their convictions for the murder were dramatically overturned.
And the Kercher family has been left feeling ignorant of the exact circumstances in which 21-year-old Meredith died in the Umbrian town on November 1 2007.
Mr Kercher, 69, from Croydon, south London, believes there "had to be" more than one killer involved - and does not seem to think the evidence points to a "random" culprit.
"They say Meredith was killed in front of her wardrobe in her room and then the body was moved across the floor and covered with a duvet," he said.
"Why would you do that if you're just a random killer?"
Yet there is little scope for the murder inquiry to be reopened and a hunt for other suspects launched, he acknowledged.
"I don't see how the investigation can be reopened if there is no other evidence, but what I would like to see is Rudy Guede coming clean and saying something," he said.
"If he was there then why doesn't he tell the truth?"
Guede, a small-time drug dealer from the Ivory Coast, has always admitted being present at Miss Kercher's cottage on the night of the murder but denies involvement.
Prosecutors claimed he collaborated with Knox and Sollecito in the killing but that version of events was rejected by the appeal court.
Meanwhile, in the four years between the murder and acquittals, Knox was turned into "some kind of celebrity" while Miss Kercher was all but eclipsed, her father said.
In his new book, Meredith: Our Daughter's Murder and the Heartbreaking Quest for the Truth, Mr Kercher turns the spotlight back on to his daughter.
Speaking just after it hit the shelves, he said: "People wanted me to write this book because they say 'we know everything about Knox but nothing about Meredith'.
"You can understand that obviously Meredith is dead while Knox, Sollecito and Guede are alive so the focus is on the people who are still part of the scenario and I think that's where the fault lay."
But he insisted he had never been "vindictive" and only wanted to present the facts in his book.
"It's up to people to read those facts and make up their own mind," he added.
Asked whether he had sympathised with Knox's parents, who made repeated high-profile bids to persuade the world of their daughter's innocence, he said: "I can understand they were fighting for their daughter's freedom but it wasn't palatable."
The Italian people, however, were 100% behind Miss Kercher, he believes.
"I don't think you would see a thing like that in Britain," he said. "I think it's because in Italy they're so family-oriented. And they know Meredith is dead so the weight of sympathy was behind her."
And although Perugia's appeal court quashed the convictions of two of the three young people originally found guilty of the murder, Mr Kercher maintained the Italian justice system was "one of the fairest".
He added: "You have to accept what happens."
The semi-naked body of Miss Kercher, a Leeds University exchange student from Coulsdon in Surrey, was found on November 2nd 2007, in her bedroom at the Perugia house she shared with Knox and others.
Her throat had been slit and her door left locked.
Knox, also a student at the time, was sentenced to 26 years' imprisonment and Sollecito to 25, but both strenuously protested their innocence from behind bars and were ultimately cleared.
Prosecutors are appealing against the acquittals to Italy's Supreme Court, with a decision expected in the autumn.
Guede was sentenced to 30 years in prison for the killing but had his jail term slashed to 16 years on appeal.