By Unjustly Accused
On the morning of November 2, 2007, Meredith Kercher, a 21-year-old exchange student from the University of Leeds, was found dead in her bedroom in a hillside cottage in Perugia, Italy. She had been sexually assaulted and stabbed. She was bright, well-loved, and far from home. Nothing that follows diminishes what was taken from her or from the family who has carried that loss for nearly two decades.
But the investigation into her death became one of the most closely watched forensic disputes of the century. Her American roommate, Amanda Knox, and Knox’s then-boyfriend, Raffaele Sollecito, were arrested within days, convicted in 2009, acquitted in 2011, convicted again in 2014, and finally, definitively acquitted by Italy’s highest court in 2015.
At the center of that eight-year whipsaw were two small pieces of evidence: a kitchen knife and a bra clasp. The clasp was not collected on the night the body was found. It was collected 47 days later, from a room that had been searched, disturbed, and re-entered in the meantime.
That single fact raises difficult questions that reach far beyond Perugia, including into cases this publication has followed closely in Kentucky.
Case at a Glance
- Victim: Meredith Kercher, 21, British student
- Location: Via della Pergola 7, Perugia, Italy
- Date of death: Night of November 1, 2007; found November 2, 2007
- Accused: Amanda Knox (then 20) and Raffaele Sollecito (then 23)
- Separately convicted: Rudy Guede, whose bloody palm print, DNA on the victim’s body, and DNA mixed with her blood on her bag and clothing were found at the scene. Guede was convicted in a fast-track trial in October 2008.
- Knox/Sollecito outcome: Convicted 2009; acquitted on appeal October 3, 2011; acquittal annulled 2013; reconvicted 2014; definitively acquitted by the Supreme Court of Cassation on March 27, 2015
- Time in custody: Nearly four years each
What Happened
Police arrested Knox, Sollecito, and a bar owner named Patrick Lumumba on November 6, 2007, following an overnight interrogation of Knox conducted without a lawyer and, as the European Court of Human Rights would later find, without adequate interpretation. Lumumba was released after customers confirmed he had been working at his bar. In 2019 the European Court ordered Italy to pay Knox €18,400 for those violations.
Soon after, Rudy Guede’s bloody fingerprints were identified on bedding beneath the victim’s body. Guede had fled to Germany. He was extradited and, rather than investigators reassessing their theory, the prosecution’s case expanded: three attackers instead of one.
The forensic case against Knox and Sollecito rested principally on two items:
- A kitchen knife taken from Sollecito’s apartment, on which police scientists reported Knox’s DNA on the handle and a trace they attributed to Kercher near the blade.
- The metal hook-and-eye clasp cut from Kercher’s bra, on which police scientists reported a partial profile consistent with Sollecito.
No trace of Knox’s DNA, fingerprints, hair, or footprints was identified in Kercher’s bedroom, where the murder occurred. By contrast, Guede’s traces were found in the room, on the victim, and on her belongings.
Why the Bra Clasp Raises Red Flags
The timeline of collection
The bra itself was collected in the first days of the investigation. The clasp, torn from it, was not. It remained in the bedroom until December 18, 2007, when forensic police returned and collected it from the floor, in a different place from where it had appeared in earlier footage.
In the intervening weeks:
- Investigators had conducted additional searches of the cottage.
- Items in the room had been moved and handled.
- The room had been entered repeatedly by people wearing gloves and shoe covers that were not necessarily changed between touches.
When the court-appointed experts, Professors Stefano Conti and Carlo Vecchiotti of Rome’s La Sapienza University, reviewed the work in 2011, they reported multiple basic departures from international collection and laboratory standards. According to coverage of their testimony, the clasp carried DNA fragments from multiple unidentified males, and the circumstances strongly suggested contamination.
In plain terms, an item that sat for seven weeks in a disturbed room, and was then picked up and passed between gloved hands, cannot tell a jury when or how a trace of DNA arrived on it.
The “hook without the cloth” problem
At trial, Sollecito’s lawyer, Giulia Bongiorno, put the problem simply: “How can you touch the hook without touching the cloth?”
The fabric back strap of the bra carried multiple traces of Guede’s DNA. It carried none of Sollecito’s. Yet the prosecution’s theory required jurors to accept that Sollecito had handled the tiny metal hook forcefully enough to leave DNA but had never touched the fabric attached to it.
Transfer, not presence
Professor Peter Gill, one of the founding figures of forensic DNA profiling, publicly argued that the clasp result was entirely compatible with transfer. Sollecito had been at the cottage in the days before the murder, and had been seen trying to force Kercher’s locked door the morning she was found. DNA from a door handle can move to a glove, and from a glove to whatever the glove touches next.
This is the same mechanism this publication has explained in When DNA Deceives: The Hidden Dangers of Touch Transfer Evidence and in Secondary DNA Transfer and the McKinney Case. DNA is not a timestamp, and it is not a story. (Later in this series, we examine how the same mechanism put a retired Liverpool taxi driver on trial for murder: David Butler.
Why the Knife Raises Red Flags
The knife was selected from Sollecito’s kitchen drawer. The defense argued that it was inconsistent with a bloody knife imprint left on Kercher’s bedsheet and with some of her wounds.
The trace attributed to Kercher was a low-template sample, meaning the quantity of DNA was so small it fell below the levels at which standard testing is considered reliable. Low-template results are especially vulnerable to:
- Stochastic effects, where genetic markers randomly appear or drop out
- Contamination, where tiny amounts of stray DNA dominate the result
- Interpretation bias, where an analyst who knows the suspects reads ambiguous peaks as a match
The independent review concluded that no reliable evidence of Kercher’s DNA had been found on the knife. When a previously untested sample from the knife was examined during the 2013–2014 retrial, it contained no DNA belonging to Kercher.
In plain terms, the “murder weapon” was a kitchen utensil from a different apartment, carrying the expected DNA of a person who cooked there and an unrepeatable trace that independent experts could not confirm.
What the Courts Ultimately Said
The 2011 appeals court, presided over by Judge Claudio Pratillo Hellmann, wrote that the original guilty verdict “was not corroborated by any objective element of evidence” and described Knox’s interrogation as one of “obsessive duration” in a language she was still learning.
That acquittal was annulled in 2013 and a Florence court reconvicted the pair in 2014. But on March 27, 2015, the Supreme Court of Cassation ended the case, not by ordering yet another retrial but by annulling the conviction outright.
The court’s written reasoning, published that September, criticized “glaring errors,” “investigative amnesia,” and “guilty omissions,” and pointed to “sensational failures” in the investigation. The court found that no “biological traces” could be attributed to Knox or Sollecito “in the room of the murder or on the body of the victim, where in contrast numerous traces were found attributable to Guede.”
Knox’s separate conviction for falsely accusing Patrick Lumumba during the 2007 interrogation followed its own path. After the European Court’s 2019 ruling, it was retried; a Florence court upheld it in June 2024, and Italy’s highest court made that ruling final in early 2025. She received no further prison time, having already served the sentence while wrongly held on the murder charge.
The Spradlin Parallel: When the Scene Stops Being a Scene
Readers who have followed our coverage of the death of Amber Spradlin in Kentucky will recognize the pattern.
In A Crime Scene Released, Then Rebuilt, we documented a home that was released within hours, then cleaned; a couch moved outside for about two days before a knife was logged as “found middle of couch on back porch”; and a biological sweep conducted a week after the scene was released.
Different country, different legal system, different facts. Michael McKinney’s case remains open and he is presumed innocent. But the scientific principle is identical:
- Evidence gathered after a scene has been disturbed carries the history of every person and object that touched it in between.
- The later the collection, the more alternative explanations a result must rule out.
- A laboratory cannot repair a collection failure after the fact.
Key Questions and Systemic Issues
- Scene control: Who decides when a scene can be released, and who is accountable when evidence is later collected from a compromised space?
- Low-template DNA: Should results below validated thresholds be admissible at all without independent replication?
- Confirmation bias: When investigators have already named suspects, how do labs protect analysts from interpreting ambiguous data to fit?
- Theory expansion: When a third person’s DNA saturates a scene, why does the theory grow to include him rather than replace earlier suspects?
What Comes Next
The Kercher case is closed. Rudy Guede was released in 2021 after serving his sentence. Knox has become a vocal advocate for the wrongly accused. Meredith Kercher’s family has spoken with dignity about how the years of litigation prolonged their grief and left them without the clarity they deserved.
That last point matters most. A flawed investigation does not only endanger the accused. It robs the victim’s family of certainty.
Why This Case Matters
- Collection timing is evidence. A clasp collected 47 days late cannot be read like one collected on day one.
- Trace DNA can travel. Gloves, door handles, and shared spaces can deposit DNA without any criminal act.
- Low-template results are fragile. Unrepeatable traces should not carry the weight of a murder conviction.
- Independent review works. Court-appointed experts exposed problems the original lab did not acknowledge.
- Interrogation conditions matter. Overnight questioning without a lawyer produced a false accusation against an innocent man.
- Victims deserve accuracy. Meredith Kercher’s family endured years of reversals because the original case was built on unstable ground.
Forensic certainty in the courtroom is not the same as scientific truth. The Kercher investigation shows how a few fragile results, collected late and interpreted with confidence, can hold two people for four years and keep a grieving family in court for eight. Confidence is not the same as certainty.
Next week, we look at a case where the problem was not what the lab found, but what a prosecutor kept from the defense: Michael Morton’s nearly 25 years in a Texas prison.
We will continue to examine how scene integrity and DNA interpretation shape cases across the country, including in Kentucky. If you have information about a potential wrongful prosecution, share it securely at Unjustly-Accused.com.
Featured image: Perugia skyline. Photo: Grifomaniacs / Wikimedia Commons (CC BY-SA 2.5).
