The child murder victim JonBenet Ramsey's DNA did not match her family despite police leaving her parents "under suspicion."
The mini beauty pageant star was six-years-old when she was found murdered just hours after a ransom note was left at her family house in Boulder, Colorado, in the US, on December 25, 1996.
More than 25 years on, no one has ever been convicted of her murder, despite DNA being found at the scene which didn't belong to anyone in the family.
But now a new book by former Texas sheriff and author John W. Anderson, Lou and JonBenet: A Legendary Lawman's Quest to Solve a Child Beauty Queen's Murder has shined light on how police kept her parents "under suspicion."
During an interview with Colorado investigator Lou Smith, who worked the case until his 2010 death, he says evidence found under the girl's fingernails and clothes did not match any family members or anyone close to the case.
Mr Anderson writes in the book: "For the past quarter-century, the Boulder police have ignored the DNA evidence that exonerated the Ramseys and could be used to identify her killer."
But despite police knowing this authorities still tried to put parents Patsy Ramsey and John Bennett Ramsey under "an umbrella of suspicion", according to Mr Smith.
This led to many believing them to be a suspect in the case and receiving death threats.
Despite the little girl's death being ruled as a homicide, the murderer has still not been found as her dad John pleaded with Colorado's governor to look into her death again.
He has requested an outside agency to be put in charge of DNA testing in the case.
It led to more than 6,400 people signing the petition which called on the state's governor, Jared Polis, to put the investigation "in the hands of a new agency that's free from Boulder’s significant history with the case".
John Andrew said: "This case garners a lot of emotion. And there's value to having an unbiased, outside investigator with fresh eyes and fresh perspective and no baggage to come in and look at this case.
"The lead investigator is someone who was at the house in 1996. That's not a positive for this case.
"The focus is making sure the same mistakes that were made in '96 won't be made today."
