For the first time, Darlene comes face-to-face with Robert Hamer, the FBI special agent responsible for her ex-husband's arrest.

"Robert, [you are] one of my heroes," Darlene says. "As secondary victims, if you will, of this crime, I truly believe that [Todd's crimes] would have continued. This would have perpetuated, and you saved my children's life and you saved my life. All the hurt that we have gone through is worth it for the lives that we are saving. So, thank you."

Catching child predators like Todd hasn't been easy, Robert says. For three years, Robert posed as a "man-boy lover" and member of NAMBLA. "I have targeted some pretty tough organizations—the Mafia, the Mexican Mafia," he says. "This was clearly the most difficult assignment that I ever undertook."

It cost Robert just $35 to become a NAMBLA member, but it took time and patience to gain the trust of their most influential leaders.