The DNA match did not deter prosecutors. They pressed on, arguing to the jury that the two men "must have met" and persuaded the jury to convict both men on the theory that Cope "served up his daughter for his and ... Sanders's own perverse pleasures" -- even though Cope never mentioned Sanders in his confessions. Cope was convicted and sentenced to life without parole. Today, he remains in prison while he seeks a new trial based on the fact that Cope's jury was not allowed to hear evidence of Sanders's contemporaneous crime spree or his jailhouse confession to another inmate that he killed the "girl in Rock Hill."



The Norfolk Four were four Navy seamen -- Danial Williams, Joseph Dick, Eric Wilson, and Derek Tice -- who confessed to participating in the rape and murder of Michelle Bosko in July 1997. Williams, a neighbor, confessed first, but his DNA did not match DNA found at the crime scene. Authorities then interrogated Joseph Dick, Williams' roommate, who confessed and also implicated Williams. When Dick's DNA did not match, the authorities again pressured the malleable Dick to name his accomplice. This time, Dick named Eric Wilson. Wilson confessed to raping Bosko, but leaving before she was killed. When Wilson's DNA did not match, Dick then identified Derek Tice. After a lengthy interrogation, Tice eventually confessed and named three other men who refused to confess. All seven men were charged with the rape and murder despite the fact that the DNA found on the victim was not theirs.



The case should have come to an end when Omar Ballard, who knew the Boskos, wrote a letter from prison to a friend in which he confessed to the killing. Ballard's DNA was a match. Two weeks before Michelle's murder, Ballard had assaulted a woman who lived down the street from Michelle and two weeks after her murder, he went on to rape a 14-year-old girl. Ballard told the police that he committed the crime by himself, but instead of dismissing the charges, the authorities pivoted and pressured Dick once again to change his story. Now, Dick said that Ballard was part of the group that gang-raped and killed Michelle. Eventually, Ballard, Tice, Dick and Williams were convicted of murder and rape and Wilson was convicted only of rape. Today, the Norfolk Four are out of prison -- thanks to a commutation of their sentences by Virginia Governor Tim Kaine -- but they still have to live with the yoke of their convictions and register as sex offenders.



Knox's case is, in some ways, even more outrageous than those of Cope and the Norfolk Four. Those men all gave detailed confessions to police during hours of unrecorded interrogations. Knox, however, never confessed to murder. She told the police -- after more than 24 hours of interrogation in a language she barely knew -- that she had invited her boss, Patrick Lumumba, back to her house and that Lumumba went into Kercher's room to have sex with her. Knox claimed she was in the kitchen and ran out of the house when she heard screams. Knox never mentioned Guede in her statements. In fact, she never mentioned Sollecito. Guede, however, cleared Knox shortly after the murder. While Guede was on the run in Germany after the crime, the Italian authorities arranged for one of his friends to call Guede via Skype. On this call -- which was surreptitiously recorded -- Guede told his friend that "Amanda had nothing to do with it."



Prosecutors in the Knox case could not even settle on a "conspiracy theory." At first, they suggested that Knox orchestrated a group-sex game that got out of control. Prosecutors simply invented this theory to give the jury a salacious motive and the press some sensationalist headlines to print. This became clear when prosecutors abandoned it in later appeals, switching to the equally implausible theory that Knox wanted Kercher dead because Kercher had complained about how messy she was.



Some, like Professor Alan Dershowitz, have suggested that Knox must be guilty because she implicated an innocent man -- Lumumba -- when she "confessed" to the authorities. But in the annals of false confessions, innocent false confessors frequently implicate other innocents. Just ask Chris Ochoa, a Texas high school honor student who named his best friend William Danziger as his accomplice in the rape and murder of a young woman in Texas. Ochoa even testified against Danziger at Danziger's trial. Both of them spent more than a decade in prison before DNA evidence proved that a rapist and killer named Achim Marino committed the crime. The fact that Ochoa caved into police pressure and named his best friend does not make him any less innocent, or Marino any less guilty. The Beatrice Six, the Central Park Five, the Dixmoor Five, the Englewood Four, and the Norfolk Four are other cases in which multiple defendants falsely implicated other innocent men and women in their own false confessions.



This pattern is no accident. Police are trained to suggest "themes" to suspects that minimize the suspects' roles and blame others for the crime. It was the police who suggested Lumumba to Knox when they misinterpreted a text message she had sent in him in Italian ("see you later") to mean that the two had planned to meet later on the evening of the murder. We suspect that the police contaminated her statement by feeding her Lumumba's name and that Knox simply bowed to their pressure to implicate him.



Once the DNA matched Guede (and after he admitted Knox was innocent via Skype), the authorities should have released Knox and Sollecito and focused their sole attention on Guede, who, like Ballard and Sanders, was a lone-wolf predator. But police tunnel vision and confirmation bias took over. Tunnel vision transpires when police lock onto a theory of how a crime occurred, thereby blinding themselves to other alternatives. Confirmation bias causes them to interpret evidence in ways that support their theory and to ignore or reject evidence that does not.



Unfortunately, for Knox and Sollecito, tunnel vision and confirmation biases are human conditions which mean that judges and juries experience them, especially in cases where confessions are involved. For years, judges and jury members have taken confessions as the gospel truth because they cannot accept that someone would ever confess to a crime -- especially a murder or rape -- that they did not commit. The truth is that there have been hundreds of proven false confessions discovered in the post-DNA age and over 80 percent of them have been in murder cases.



The hopes and fates of Knox, Sollecito, the Norfolk Four, and Billy Wayne Cope now depend on the willingness of Italian and American authorities and courts to learn what the U.S. Supreme Court recognized in Corley v. United States in 2009: The pressures of police interrogations are so immense that they can induce "a frighteningly high percentage of false confessions."



There's a second lesson that they must also learn: When DNA evidence tells a different story than a confession, the DNA should trump the confession. That's why DNA is the gold standard. Confessions, however, are often no more than "Fool's gold."



Finally, perhaps the most enduring lesson from the study of wrongful conviction cases is that convictions are on shaky ground when prosecutors have to invent "conspiracy theories" in order to save them or are constantly switching theories to explain away DNA.