(From the publisher):
Nancy and her father have come to Philadelphia to attend a meeting of the Vidocq Society, a group dedicated to the investigation of unsolved crimes. One of Carson's clients was recently tried for murder, but the Drews are the only ones who believe in his innocence. Enter the Hardy clan to prove his guilt. It's a high profile case where everyone has something to lose.
Original title: A Question of Guilt
Genre: Fiction→ Children & Young Adult→ Mystery