Experts say that there are two possibilities for that apparent gap: that Sandusky stopped molesting boys for a period of time, or, more likely, that there are more victims of Sandusky's abuse who have not come forward or been identified by police.
"My bet would be that there would be more victims out there," said John Seryak of the organization Stop Educator Sexual Abuse and Misconduct. "If he was still very active in his organization The Second Mile, his access to children would be immediate. He obviously is a super skilled predator. It would be surprising that he wouldn't act or spend that whole time grooming."
For Sandusky, this could have led to a hiatus in his behavior that then could have resumed around 2004, according to Ken Singer, a social worker who treats pedophiles and a past president of Male Survivor, a network for survivors of sexual abuse.
"I've worked with offenders who have recidivated after a number of years," Singer said. "It's not that the desires or the impulses are not there but the degree of control, which could be anything from a spouse keeping a good watch on him that keeps him from acting on impulse, it could be disgust with self and promises not to do this again, but then they hit a situation where they go back to other behavior."
Singer compared the behavior to that of an alcoholic.
"It's similar to an alcoholic that has been drinking for years then stops because of internal conditions, he's sick of drinking or whatever, finds sobriety, goes to AA, doesn't drink again for a number of years but then falls off the wagon and resumes his former lifestyle," Singer said.
While it is possible that Sandusky did stop for the years 2001 to 2004, Seryak said that it is unlikely. Pedophiles, they explained, can rarely control their impulses.
"If somebody was scared straight, he would want to disassociate from the organization," Seryak said. "That's not to say that when there was a report made in 2001 that it wasn't some sort of a wake-up call, but child molesters never really get wake up calls. There is strong evidence that they can't be rehabilitated."
"Make no mistake about it," he said. "These predators have a compulsiveness that's extraordinary, beyond what any of us could ever imagine."