The Hunt for the Zodiac Killer

A new hunt for the Zodiac Killer gains unprecedented access to files, unearthing a complicated cypher that may contain the killer's name. A prime suspect with code training emerges.

The hunt uncovers clues that the Zodiac Killer may have served in the U.S. Armed Forces, as the team's supercomputer identifies symbols in the killer's code that only a few would know.

The hunt uncovers a bizarre new cipher related to the Zodiac Killer, and the team's supercomputer uncovers a weird lunar pattern linking the killings. A second prime suspect emerges.

The FBI releases secret files on the mysterious Zodiac Killer, and a handwriting analyst connects the Zodiac's letters to a taunting letter mailed 3,000 miles away in Albany, NY.

Sal and Ken investigate in San Francisco, the epicenter of the Zodiac Killer murders, as the Code Team announces extraordinary news: A team member has solved the Zodiac's infamous Z-340 code, which has eluded codebreakers for 50 years.