This Flick is extremely vague.
SPOILERS.
It looked liked he DID molest that child when he fell for Meryl Streep's bluff and left, but he could have left for many reasons, he could have left because he in fact DIDN'T do anything, but was worried that they would still believe her, he may also have left because of the stigma that would have stayed on him example just being accused of a crime will get people associating you with it even if you're innocent.