"Now they have absolutely nothing to keep an eye on this guy," said California criminal defense lawyer Kevin McDermott. "No reporting requirements. No monitoring requirements whatsoever."
"He must be Teflon," McDermott said.
At the heart of Karr's freedom is a piece of lost hardware -- the computer he allegedly used to possess sexual images of children.
That computer, which served as both evidence and a crime scene, was nowhere to be found. It was lost by investigators when they moved from one storage facility to another in 2002.
"I'm not that surprised that evidence would get lost or disappear. … It's been sitting there for five years" said McDermott, who has worked on sex crimes.
Karr has only the botched evidence to thank for his freedom.
Possession of child pornography in California is a misdemeanor for first-time offenders, which means they can easily escape charges by simply moving to another state.
"That's how guys like this get away," McDermott said. "They get slapped on the wrist, and then they get smarter about how they go about offending."
A solution to this legal loophole, McDermott believes, might be to make child pornography possession a felony no matter what, even if it's a first offense.
But in the interim, the former prosecutor and father of two will simply try doubly hard to keep his children away from wandering predators.
"There's just no accounting for people like this. All you can do is make sure your kids don't fall into this trap," he said.
"You have to teach your kids to be aware that people like that are out there -- as tough as it seems that you have to limit how friendly you are."
Dropping a case because of lost evidence may seem like a failure of the justice system, an accident that let a probable pedophile and possible molester go free.
But perhaps the greater failure of justice is that it has failed JonBenet: Ten years after her death, there are no leads in sight.
The crime scene has been scrubbed clean as the Ramsey home was bought and sold by new owners.
"I don't think it's ever it's going to be solved," said former prosecutor Wise.
"If you don't have a DNA match after 10 years, I think [chances are] really thin," he said.
The best hope for the people of Boulder -- and, of course, for JonBenet -- is that someone will step forward to confess and that this time, it will be for real.