Creepy kid-lover John Mark Karr may have been set free as a bird after DNA failed to link him to the killing of JonBenet Ramsey — but a new report says authorities still think he may have had some role in the 6-year-old beauty queen's horrific death.

The federal government is investigating Karr for a link to JonBenet, and fears that he may have been part of some larger conspiracy to kill her, a prober told the CBS news show "48 Hours Mystery" in an episode airing tonight at 10 p.m.

CBS reporter Erin Moriarty says the feds are still suspicious about Karr because of the way he talked about the killing and his love of little girls in e-mail letters to a University of Colorado journalism professor named Michael Tracey.

"He is still being investigated for two reasons," Moriarty said. "Because much of what he put on e-mail and said to Michael Tracey has panned out, and there could be children who could be harmed by John Mark Karr."