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.