Pictures of girls ' faces on photos of adult nude bodies lead to suspicion . Investigators do not believe he had any contact with the three girls . Child 's face next to pictures indicates ` ` simulated sexual activity , '' official says . `` It 's definitely on the increase , '' said Justin Fitzsimmons , a former prosecutor and senior attorney with the National Center for the Prosecution of Child Abuse , part of the National District Attorneys ' Association . ` ` Virtual Reality '' cases such as this present a unique legal challenge .
Pictures of girls ' faces on photos of adult nude bodies lead to suspicion . Investigators do not believe he had any contact with the three girls . Child 's face next to pictures indicates ` ` simulated sexual activity , '' official says . ` ` Virtual Reality '' cases such as this present a unique legal challenge .