S1 E4 ∙ The Secret FBI Files ∙
The FBI releases secret files, and a handwriting analyst connects the Zodiac Killer's letters to a taunting correspondence mailed 3000 miles away in Albany, New York.
G
Contains Mature Themes
All episodes for series 1 of The Hunt for the Zodiac Killer
S1 E1 · The New Suspect
As investigators revisit the case of California's Zodiac Killer, a suspect with code training emerges.
S1 E2 · The Military Connection
The hunt uncovers clues that the Zodiac Killer may have served in the US Armed Force.
S1 E3 · A New Code Uncovered
A mysterious new cipher related to the Zodiac Killer is discovered.
S1 E4 · The Secret FBI Files
A handwriting analyst studying the Zodiac Killer's letters makes a startling connection.
S1 E5 · The Code is Cracked
A team member solves the Zodiac's infamous Z340 code.
