With all due respect to Rapier57, I would not recommend calling the police unless you are REALLY sure about this. The mere accusation of something like that can cause irreparable damage to someone's reputation, career, and psyche.

I will also state that I detest child pornography and if this person is knowingly storing and/or distributing it then the full force of law should be used to punish that person for the crimes committed, but please be very careful before calling in the police.