Colorado prosecutors will not charge schoolteacher John Mark Karr with the murder of 6-year-old JonBenet Ramsey after tests showed his DNA does not match DNA found in her underwear, it was announced today.
The decision by Boulder County District Attorney Mary Lacy to drop her arrest warrant against the 41-year-old school teacher was made public about an hour before he had been due for his first Colorado court appearance.
That hearing was cancelled.
The county sheriff's office initially reported that Karr was freed from jail but later said he would remain in custody because authorities in northern California had asked that he be turned over to them to face child pornography charges.
The DNA found on the underwear of JonBenet was identified as belonging to a white male but has never been matched to a suspect in the murder, which for 10 years has baffled police and fascinated Americans.
Amid scepticism over Karr's claims to have been with the former Little Miss Colorado when she died, legal experts have said that it would be difficult to bring the case to trial without a DNA match.
That conclusion was borne out in the five-page court filing issued by the district attorney.
"Wherefore no evidence has been developed other than his own repeated admissions to place Mr Karr at the scene of the crime, and in particular because his DNA does not match that found in the victim's blood in her underwear, the people would not be able to establish that Mr Karr committed this crime despite his repeated insistence that he did," the filing said.
Prosecutors also said in the document that they moved quickly to have Karr taken into custody because he had begun to "express sexual interest in specific young girls he said he had met" at the school in Thailand where he had recently been hired.
Karr said publicly after his arrest that he loved JonBenet and was with her when she died by "accident." But members of his family have insisted he was out of state at the time of JonBenet's murder and could not have been involved in the crime.
JonBenet's parents, who were once said by authorities to be under an "umbrella of suspicion" in their daughter's death, were also excluded from having left the DNA. Her mother died of cancer in June this year.
Other evidence at the crime scene included a foot print found near JonBenet's body in the basement of her home and a palm print on a nearby door.
JonBenet's father, John Ramsey, found the girl's battered body in the basement on December 26, 1996, about seven hours after her mother stumbled on a bizarre letter claiming that she had been kidnapped and demanding $US118,000 ($NZ187,000) ransom.
JonBenet had been strangled to death with a garrote made from cord and a paint brush found in her mother's paint supplies, her skull fractured and her mouth duct-taped. Forensic evidence suggests she had been sexually assaulted.