Boulder, Colo. ? The Colorado prosecutor admitted Tuesday officials didn’t check out John Mark Karr’s story until after they’d spent $10,000 flying him back from Thailand.

Boulder Dist. Atty. Mary Lacy also acknowledged that critics wanted to see her “tarred and feathered” after Karr’s DNA failed to match stains on slain 6-year-old JonBenet Ramsey’s underwear.

But Lacy said authorities went after Karr because the DNA “surreptitiously” snagged from him wasn’t adequate for testing – and because in e-mails to a Colorado journalism professor he spoke of seducing another young girl.

“We also consulted a forensic psychologist,” Lacy said. “It was his opinion that this person was dangerous.” She added: “I think we did a good job for the community.”

In a court hearing Tuesday, Karr agreed to be extradited to California to face misdemeanor charges of child pornography possession.