As more details of John Mark Karr's confession to the killing of JonBenet Ramsey surface, several aspects of the former schoolteacher's account raise questions about his role in the 6-year-old's death in 1996.
Karr claims he drugged JonBenet and then had sex with the child, but an autopsy said a blood screening showed no drugs or alcohol in the child's body. Also, while Karr reportedly claims to have sexually assaulted JonBenet, no semen was found on her body. However, the little girl did have small vaginal abrasions.
Karr has not yet been formally charged, Boulder, Colo., district attorney Mary Lacy said in a news conference Thursday, adding that there is "much more work" to be done in the case. She warned the public not to "jump to conclusions," and suggested that the arrest may have been forced by other circumstances, including the need for public safety and fear that Karr might flee.
Karr's ex-wife, Lara Karr, who divorced him in 2001, told KGO-TV in San Francisco that during the 1996 Christmas season, when JonBenet Ramsey was strangled and beaten to death in Colorado, she and her then-husband were living in Alabama — and that she was with him the entire season.
A Thai police official said Karr told Thai interrogators that he picked up JonBenet at her school and brought her to the basement the day she was killed, Dec. 26, 1996, the day after Christmas — a highly unlikely scenario.
DNA was found beneath JonBenet's fingernails and inside her underwear, but Wood said two years ago that detectives were unable to match it to anyone in an FBI database. It was not known whether investigators had any DNA evidence against Karr, despite serving time in a California jail in 2001 on child pornography charges. Sonoma County Chief Deputy District Attorney Joan Risse confirmed the pornography charges and an outstanding arrest warrant against a John M. Karr, though she didn't know if he was the same person being held in the Ramsey case.
CBS News 48 Hours correspondent Erin Moriarty reports that investigators may have arrested Karr this week not because they had definitive evidence linking him to the Ramsey murder, but because they feared he might hurt a child in Thailand.
A former Boulder district attorney who investigated the Ramsey case tells Moriarty he has serious doubts about any confession because of the amount of public information surrounding the case. "I am very concerned about the viability of this case today, it does not sound to me like they've done their homework sufficiently to have arrested him at this time," says Trip DeMuth.
But the deciding factor will be the DNA evidence found at the crime scene.
"I think if this DNA excludes this suspect, this prosecutor has a serious problem on her hands," DeMuth says.
Sources tell CBS News tests have been conducted, but the results are not yet known. 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.
If the DNA does not match Karr's, this won't be the first time investigators thought they had evidence leading to the killer.
No evidence against Karr has been made public beyond his own admission. U.S. and Thai officials did not directly answer a question at the news conference Thursday about whether there was DNA evidence connecting him to the crime.
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."