Since you are convinced he is what you say he his it begs the question - Have you notified the local authorities? If so, what was their response? Have you notified the school where he's teaching? How did you find out he's a paedophile? Have you notified the embassy of his country of origin? It's a serious allegation Roberta and I hope you are willing to do everything possible to protect the children at whatever school he's teaching at.
I'm not sure that posting your allegation here is going to do much good, but I suppose it's a good starting point.