These are the books by David Belbin that are reviewed on this site:
Disturbing story of false accusation and betrayal. Bewildered and isolated,Jon confesses to a crime that he did not commit.
On holiday on a Greek island, Cassie becomes pre-occupied by the mythical harpies. Have they really come back to seduce the boys away, including her own brother, or is she just feeling left out of the action? And where is Ben anyway?