Each year some 725,000 children are reported missing in America. The vast majority have gotten lost, run away or been abducted by parents embroiled in custody battles; in most such cases the child returns home unharmed. Roughly 4,400, however, are taken each year by nonfamily members, most of whom prey upon children for sexual purposes, then release them a short time later. Of those cases some 100 result in murder.

Few are better versed in these statistics than Ernie Allen, president of the National Center for Missing and Exploited Children in Alexandria, Va. Allen, 56, first became interested in the problem more than 20 years ago while serving as director of public safety for the city of Louisville, Ky. Back then, he recalls, "you could report a missing gun or a stolen car to the FBI, but there was no mechanism to report a missing child." Thanks in part to Allen's efforts, Congress passed a law in 1990 that requires local law enforcement to immediately report disappearances to federal authorities. The NCMEC, a national clearinghouse for prevention and rescue information, was mandated by Congress in 1984. Allen shared advice for parents with correspondent Colleen O'Connor.

Dual abductions are highly unusual. Is any aspect of the Oregon City situation familiar?

Actually this tragedy fits the national profile: an 11- or 12-year-old girl taken from within half a mile of her home. About half the children who are abducted are 13 or younger, and two-thirds are girls.

Is there a standard predator profile?

We have to debunk the myth of "the dirty old man." The vast majority of these crimes are committed by males 35 or younger. We also can't rely on the idea that nonparental abductions are the work of total strangers. We have learned from the predators themselves that typically they first insinuate themselves into a child's life by befriending the child, asking for directions or help, hanging around the playground. They become familiar in order to be able to quietly lure children rather than grab them.

How should parents teach a child to handle a threatening situation?

We urge children to remember three steps: No, Go and Tell. They should know it's okay to resist adults and make noise, yelling things like, "This man is not my father!" They should run away if they can. And if they break loose, they can help identify their abductors by remembering details and telling a trusted adult.

What should you do first if you think your child is missing?

Call the police immediately, even if you're not sure. Stay calm. Before the police arrive, prepare a detailed description of your child that includes height, weight, birth date and any special identifiers, such as glasses or scars. Parents should also request that the case be reported to the FBI and call our hot line (1-800-THE-LOST).

Are there precautionary steps?

All parents should keep on hand a recent color photograph of the child; write a description of your child; get copies of your child's dental charts; know how to get hold of his medical records; arrange with local authorities to have your child's fingerprints taken and put on file. With younger children, you should know where your children are at all times, especially in public places. With older children, talk to them, listen to them, tell them they should not be embarrassed to tell you if something unusual happens. Be sure your child knows the phone number and address for both you and another trusted adult. A child should also know that if someone approaches him at school claiming to be there at a parent's request, he should call you to confirm that or ask a teacher to place the call. Finally we should balance this information carefully so that kids are not frightened. These incidents, tragic as they are, are thankfully rare. Being prepared doesn't mean being terrified to go out in the world.