https://www.youtube.com/watch?v=dptiYHeQJgc
The primary evidence used to convict Amanda Knox (and her then-boyfriend Raffaele Sollecito) of the 2007 murder of Meredith Kercher in Perugia, Italy, centered on contested DNA findings, Knox’s statements during interrogation, mixed blood traces, and behavioral/circumstantial points. They were convicted in 2009, acquitted on appeal in 2011, reconvicted in 2014, and definitively acquitted by Italy’s Court of Cassation in 2015 (which cited “stunning flaws” in the investigation and an absolute lack of their biological traces in the murder room).
Rudy Guede was separately convicted (in a fast-track trial) of the murder and sexual assault; his DNA, fingerprints, and footprints were found extensively at the scene and on/in Kercher’s body. Prosecutors argued Knox, Sollecito, and Guede acted together (e.g., a sex game or assault that escalated), but the final high court ruling rejected this for Knox and Sollecito due to evidentiary problems.
Key Prosecution Evidence
The “double DNA knife”: A kitchen knife from Sollecito’s apartment (found days after the murder). Prosecutors claimed Knox’s DNA was on the handle and a tiny amount of Kercher’s DNA on the blade, presenting it as the murder weapon. Knox’s DNA on the handle was not surprising (she cooked there); the blade sample was low-copy-number DNA, not double-tested per standard protocols, tested negative for blood, and was later judged unreliable/possibly contaminated. Experts also testified the blade did not match the wounds or a bloody knife outline on the bedding.
Bra clasp DNA: A clasp from Kercher’s bra (cut/torn off during the attack), photographed at the scene but collected ~46 days later after being moved. It was said to contain Sollecito’s DNA (the main forensic link placing him in the room). Defense and independent experts highlighted contamination risks (poor handling, multiple male DNA profiles present, low-copy DNA) and the long delay before collection.
Knox’s interrogation statements: After lengthy overnight questioning (without a lawyer present for key parts), Knox signed statements placing herself at the cottage during the crime and implicating her boss Patrick Lumumba (later cleared; she was convicted of slander for this, a conviction that has persisted in some form). Prosecutors treated the statements as evidence she was present and lying. She later retracted them, citing pressure, confusion, and suggestion.
Other forensic/circumstantial points: Mixed Knox/Kercher DNA or blood traces in other parts of the cottage (e.g., bathroom or a flatmate’s room, some revealed by luminol); a bloody bathroom footprint initially attributed to Sollecito (later challenged as a mismatch or more consistent with Guede); claims of multiple attackers based on wound patterns and lack of defensive injuries under Kercher’s nails; Knox and Sollecito’s post-murder behavior (e.g., shopping, perceived lack of emotion, alibi inconsistencies); and the staged burglary narrative.
Why the Evidence Was Contested and Ultimately Rejected
Independent experts (including court-appointed ones on appeal) found the DNA samples unreliable due to low quantity, lack of proper protocols for low-copy DNA, negative blood tests, and high contamination risk from crime-scene handling and lab procedures. No fingerprints, hairs, skin cells, or other DNA of Knox or Sollecito were found in Kercher’s room or on her body—highly unusual for a close-quarters violent struggle if they participated. Guede’s traces dominated the scene. The 2011 appeal and final 2015 Cassation rulings emphasized investigative errors, confirmation bias after the initial statements, media pressure accelerating a flawed probe, and the absence of reliable biological links.
The case remains polarizing; some earlier court explanations accepted the DNA and multiple-attacker theory, while later definitive rulings and many forensic experts did not. Knox has maintained her innocence throughout.