The biggest true crime podcast is tackling one of the most infamous serial killers of all-time in a massive four-part series.

Casefile has just dropped the first part of their series on the Zodiac Killer, who terrorised Northern California in the ’60s.

Most famously, the killer would taunt law enforcement and local media with letters containing part of a cryptogram, which they demanded be printed, usually in the next day’s edition of the paper.  They would sign these letters off with a crosshair-like symbol.

While the killer’s identity remains unknown, we can’t wait to see how Casefile’s series plays out.