I Will Find You by Harlan Coben

 David wakes up in the middle of the night and goes to check on his young son, Matthew--only to find Matthew beaten to a bloody pulp in his bed. David can't imagine who would have done it--but the cops think he did, and he goes to prison for life. Five years later, his sister in law Rachel comes to visit him with a photo she got from a friend. It was taken at a corporate event at Disney World--and in the background is young boy who looks strikingly like an older version of Matthew. David is determined to find his son and find out who framed him. And so begins quite the page-turner of an adventure.