If I found out that someone had even touched my son/daughter inappropriately ONCE, I would stop what I was doing the second I found out, spend the whole day trying to find where they lived (this is important - they must not be able to see the light of tommorow) and then hide in their house with a fish filleting knife and a spirit level (and a sharpening stone, so I could sharpen the knife for however many hours they take to arrive)
The SECOND they appear, I will cut off their cock, balls, and hands and stamp them all up their arse until I can't see a single fingernail hanging out and then stamp on their head, until it is completely level with the carpet (this will be checked with the spirit level).