These sordid crimes aren't new. If they were, children wouldn't have grown up for centuries hearing fairy tales of boys and girls being chased by wolves, eaten by mean old witches or pursued by giants who hide in the leafy heights of a beanstalk. Child predators always have been in the midst.

The difference today, however, is that children also have to be ready to run from ravenous wolves who can change their appearance and demeanor at will, who can turn from friendly cyber-chatters on computers one instant to wicked witches the next, and who chase children across the Internet with a desire to grind their bones for their own gratification.

That much has been made abundantly clear — again — in recent days with three men being charged in Utah, all in separate cases, for traveling across state lines to have sex with minors. Perhaps the most notorious of these involves allegations that Mark Turner, an Idaho native, may have come to Utah on more than one occasion to commit these crimes before he stumbled on an undercover federal agent. Authorities urge anyone with connections to the screen name "mark_2424t" to contact them.

All of this makes us glad that the new U.S. District Attorney for Utah, Brett Tolman, has announced he will focus on finding child-sex offenders. This mirrors a similar focus recently announced by U.S. Attorney General Alberto Gonzalez.

But while Utahns should be glad, they should not be relieved. In the past, investigators on all levels of government have described finding these predators online as being as simple as setting out picnic food to attract ants. To many of these criminals, the need to satisfy their urges exceeds the fear of getting caught. Often, undercover investigators barely create a new online "child" identity and enter a chat room before they are approached. Clearly, there are not enough resources available to investigators to keep up with all the scum out there ready to prey on children.

The only defense is for parents to be actively engaged in their child's online activities, to strongly forbid them from using chat rooms, and to keep any Internet-connected home computers in clear sight and in parts of the home that receive frequent traffic. Perhaps the most frightening part of the case against Turner is that authorities allege he instructed the online investigator, whom he thought was a 13-year-old girl, to leave a note telling her parents she had run away from home with two friends, and then to dye her hair.

Had his victim been a real girl, and had she followed his instructions, police would have had as difficult a time finding her as they would finding Hansel and Gretel.