The Hunt for the Zodiac Killer (2017)

S1E2 The Military Connection

Title: The Military Link Plot: As the investigation progresses, the team discovers that the Zodiac Killer might have a military background. Their advanced supercomputer detects unusual symbols within the killer's ciphers, which were likely familiar to only a select group at the time. Meanwhile, Sal and Ken stumble upon fresh leads that could bring them closer to identifying the elusive murderer.