Ralph A. Spinelli
В роли: Self - Former Solano County Saloon Owner (как Ralph Spinelli)

Donald Cheney
В роли: Self - Former Friend of Arthur Leigh Allen

Santo Paul Panzarella
В роли: Self - Friend of Donald Cheney & Acquaintance of Arthur Leigh Allen (как "Sandy" Panzarella)

Norman Boudreau
В роли: Self - College Friend of Arthur Leigh Allen

George Bawart
В роли: Self - Vallejo Police Dept (Ret)

Роберт Грэйсмит
В роли: Self - Author of 'Zodiac' and 'Zodiac Unmasked'

Ken Narlow
В роли: Self - Napa County Sheriff Dept (Ret)

Sharon Pagaling Hagon
В роли: Self - Criminal Profiler

Donald Fouke
В роли: Self - San Francisco Police Dept (Ret)

David Slaight
В роли: Self - Napa County Sheriff Dept (Ret)

Nancy Slover
В роли: Self - City of Vallejo '355' Operator

Kim Rossmo
В роли: Self - Research Professor, Department of Criminal Justice, Texas State University (как Dr. Kim Rossmo)