Kill the Messenger - S2.E8

After a bike messenger, carrying a package with content that is able to free a wrongly convicted man from prison, is brutally murdered, Castle and Beckett need to investigate the case. But they are surprised to find out that the tragic death is linked to another murder case previously investigated by Captain Montgomery. Now, in order to solve the new murder, Castle and Beckett must dig deep and discover all the secrets of a prominent New York family.