One of the most mysterious and notorious serial killers in U.S. history is known only as “Zodiac.” In the late 1960s, the spree of terror started in Northern California. The killer, who has never been caught, sent cryptic letters full of ciphers and threats to the police and the media. His victims were typically young couples who were brutally slain in isolated regions, and he left unsettling symbols, such as a crosshair symbol, at the scenes.

Murders and shootings committed by the Zodiac Killer began in 1968 and continued into the early 1970s. There was a massive manhunt and many people were considered suspects, but the culprit was never found.

Deciphering his cryptograms is a popular topic among true crime fans and armchair detectives. The Zodiac Killer is one of the most mysterious and infamous serial killers in history because of his ability to elude capture and his propensity for tormenting law authorities.