This is standard child-molester tradecraft. The successful pedophile does not select his targets arbitrarily. He culls them from a larger pool, testing and probing until he finds the most vulnerable. Clay, for example, first put himself in a place with easy access to children—an elementary school. Then he worked his way through his class. He began by simply asking boys if they wanted to stay after school. “Those who could not do so without parental permission were screened out,” van Dam writes. Children with vigilant parents are too risky. Those who remained were then caressed on the back, first over the shirt and then, if there was no objection from the child, under the shirt. “The child’s response was evaluated by waiting to see what was reported to the parents,” she goes on. “Parents inquiring about this behavior were told by Mr. Clay that he had simply been checking their child for signs of chicken pox. Those children were not targeted further.” The rest were “selected for more contact,” gradually moving below the belt and then to the genitals.

The child molester’s key strategy is one of escalation, desensitizing the target with an ever-expanding touch. In interviews and autobiographies, pedophiles describe their escalation techniques like fly fishermen comparing lures.