Beginning in the sweltering summer of 1976, fear rippled through boroughs of Manhattan when a serial murderer dubbed Son Of Sam embarked on a killing spree using a .44 calibre revolver. When David Berkowitz was arrested and convicted, New Yorkers collectively breathed a sigh of relief, but journalist Maury Terry was convinced the accused couldn't have acted alone. He spent decades trying to prove his theory, losing almost everything in the process. Filmmaker Joshua Zeman explores Terry's extraordinary crusade in this documentary series, which combines archive news footage and interviews with people connected to the Berkowitz case. The four episodes consider the possibility that police should have been hunting more than one Son Of Sam.