BOULDER, Colo. -- For a moment, it seemed the decade-old mystery surrounding the slaying of a child beauty queen had been solved. But authorities Thursday cautioned against rushing to judge the schoolteacher who made a stunning confession that he killed JonBenet Ramsey.
For now, the only public evidence against John Mark Karr are his own words. And questions have already been raised about the details of his story, including whether he drugged the girl, sexually assaulted her or was even in Colorado at the time of the slaying.
Those questions led some to wonder whether Karr was the answer to the long-unsolved slaying or a disturbed wannabe trying to insert himself into a high-profile case.
"We should all heed the poignant advice of John Ramsey," Boulder County District Attorney Mary Lacy, quoting the little girl's father. "Do not jump to conclusions, do not rush to judgment, do not speculate. Let the justice system take its course."
Paraded before a raucous crush of reporters in Bangkok, Thailand, the sullen Karr told how he loved JonBenet, was with her when she died but that her death was an accident. And while vague on the details -- "it would take several hours" -- he answered flatly when asked if he was innocent: "No."
"The bottom line is that they now have a confession and until and unless they can corroborate that confession with either physical evidence or strong circumstantial evidence, that's all they have," said Scott Robinson, a Denver attorney who has followed the case from the beginning.
Added former Denver prosecutor Craig Silverman: "I have to believe they have more than this kooky confession."
Karr told investigators he drugged and sexually assaulted the little girl before accidentally killing her in her Boulder home, according to a senior Thai police officer who was briefed about the interview with U.S. authorities.
Yet JonBenet's autopsy report found no evidence of drugs, saying her death was caused by strangulation after a beating that included a fractured skull. And while it describes vaginal injuries, it makes no conclusions about whether she was raped.
Karr's ex-wife told TV reporters she cannot defend him, then insisted he was with her in Alabama during Christmas 1996, when JonBenet's battered body was found in the basement of her home. And authorities have not said whether Karr could have written the detailed ransom note found in the Ramsey home, with its demand for $118,000 (the bonus that had recently been awarded to the girl's father, John Ramsey).
Even the Colorado professor who swapped four years' worth of e-mails with Karr and brought him to the attention of prosecutors in May refused to characterize the suspect either as killer or kook.
"I don't know that he's guilty," said Michael Tracey, who teaches journalism at the University of Colorado. "Obviously, I went to the district attorney for a reason, but let him have his day in court and let JonBenet have her day in court and let's see how it plays out."
Karr himself added to the mystery, telling The Associated Press in Bangkok that JonBenet's death was "not what it seems to be."
Asked what happened when JonBenet died, he said: "It would take several hours to describe that. It's a very involved series of events that would involve a lot of time. It's very painful for me to talk about it."
Any previous relationship between Karr and the Ramseys remained a mystery Thursday, though both have ties to suburban Atlanta. District Attorney Lacy refused to discuss the case during a brief news conference and suggested Karr's arrest may have been forced by concern over public safety and fears the suspect might flee.
"There are circumstances that exist in any case that mandate an arrest before an investigation is complete," Lacy said.
Karr, 41, was arrested at a Bangkok apartment Wednesday, a day after he began teaching second grade at an international school, Lacy said.
Hours later, Thai authorities sat him before a crowded room of news crews. Karr stunned reporters by admitting: "I was with JonBenet when she died. Her death was an accident."
"I am so very sorry for what happened to JonBenet," Karr told the AP.
Legal experts said DNA evidence will likely be key: DNA was found beneath JonBenet's fingernails and inside her underwear and authorities have never said whether it matches anyone in an FBI database. U.S. and Thai officials did not directly answer a question at a news conference about whether there was DNA evidence connecting Karr to the crime.
Karr was given a mouth-swab DNA test in Bangkok, according to a law enforcement official who spoke on condition of anonymity because of the ongoing investigation. The results of that test were not immediately known. Karr will be given another DNA test when he returns to the United States in the next several days, the official said.
Karr will be taken within the week to Colorado, where he will face charges of first-degree murder, kidnapping and child sexual assault, Ann Hurst of the Department of Homeland Security told reporters in Bangkok.
Lin Wood, the Ramsey family's longtime attorney in Atlanta, said Karr went to great lengths to conceal his identity in e-mails to the university professor, going so far as to use a computer server in Canada.
Asked if authorities could tell whether Karr had firsthand knowledge of the murder or had just picked up information from news accounts, Wood said: "There is information about the murder that has never been publicly disclosed." He did not elaborate.
Karr's ex-wife, Lara Karr, was quoted by San Francisco television station KGO saying she was with her former husband in Alabama at the time of JonBenet's killing and she does not believe he was involved in the homicide.
Denver attorney Larry Pozner, past president of the National Association of Criminal Defense Lawyers, said there were "serious questions" about the case.
"I hope we have found the murderer of JonBenet, but I have not heard the evidence that compels that conclusion," he said.
Karr's description of the case as an accident also rang false to experts.
"It's hard to imagine a more intentional, deliberate murder than hitting a little girl in the head so hard that she had almost a foot-long fracture in her skull and then deliberately fashioning a garrotte to twist until it buries in her neck and slowly stops her breathing," said Silverman, the former Denver prosecutor. "This has always been a case of deliberate murder."