I'd hate to see innocent people convicted of a crime of this sort, but from what I've seen the police suspected it might have been the caretaker and his girlfriend a fair while back. Apparently they wanted to let them 'hang themselves' when they came in for voluntary questioning. I can think of no more fitting evidence to this than the fact that half way through this questioning they say something that suddenly prompts the police to go digging in the school and find a mass of evidence including the girls' clothes. Then at 4am, they're arrested... What I can't see is any possible link to an american. The crime had no witnesses, in daylight, in a town where so many people knew each other, making the prime suspects those people that the girls knew, and not an outsider. The last 'actual' sighting of the girls was by CCTV right by the caretaker's home. The caretaker was the only person in the town who thought the girls were already dead, whilst the police and residents were all still hunting for them alive. Sorry, but this suggestion seems like a ridiculous tangent to me...