The FBI is comparing information found on computer equipment belonging to the man once suspected in the slaying of former child beauty queen JonBenet Ramsey, to data on a national database of child porn victims, a country attorney said Monday.

The digital files found on John Mark Karr's computer are unrelated to the current child porn possession case against the defendant, but contain pornographic images of teenagers, said Deputy Sonoma County Counsel Anne Keck. The FBI is trying to determine whether child porn victims from the database appear in the photos, she said.

The search marks the latest potential legal quagmire for Karr, a former teacher whose arrest in Thailand last month raised hopes that the 1996 murder of Ramsey, a 6-year-old beauty queen in Boulder, Colorado, may finally be solved. Karr had suggested that he killed the girl, but the case quickly collapsed after DNA failed to connect him to the crime.

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The disclosure came at a Sonoma County Superior Court hearing over whether to unseal police documents related to what authorities have called an ongoing investigation since Karr was returned from Colorado to face the five-year-old child pornography charges.

Karr, 41, had fled the misdemeanor charges of having five child porn images on his computer when he was first arrested in April 2001.

Judge Cerena Wong had sealed affidavits and other documents after prosecutors said it could harm the child pornography investigation and prejudice potential jurors. She refused to unseal the documents, as requested by local media.

Defense lawyers did not comment on the new twist in the case, but renewed efforts to get child pornography charges dismissed and filed a motion to exclude newly discovered computer evidence from his case.

Investigators conceded they lost Karr's computer, but claim to have found copies of the data. It was not immediately clear what files the FBI was reviewing.

Karr appeared in court briefly looking tired and worn after spending more than two weeks in a Sonoma County jail, where he remains in custody.

His lawyer asked if he understood he had a right to be present at the hearing and whether he wanted to give up that right. He answered "yes" in a soft voice and was led away by sheriff's deputies.

On Friday, Wong refused to dismiss charges against Karr, but she criticized authorities for losing evidence and failing to immediately notify her it was missing.

Karr's trial was originally scheduled Monday, but it was postponed for further hearings Tuesday on defense motions to dismiss the case or throw out newly revealed computer data.

Karr rejected a plea deal that would have put him on probation.

Prosecutors have conceded he probably will not serve more time in prison if convicted because he already spent several months in jail awaiting trial five years ago. But they want him to register as a sex offender.