In 2007, director David Fincher helmed the movie simply entitled, Zodiac, which tells the thrilling story of a rash of killings in the 1960s and 70s.

Despite the film's failure at the box office, the subject is one that seems to pique the public's interest whenever it's mentioned.

In fact, it was just a few months ago during this year's presidential race in the United States when an internet meme led to a conspiracy that Republican Senator Ted Cruz was compared to an infamous serial killer known only as the Zodiac Killer.

The conspiracy grew enough attention that Cruz's wife even replied to the comments, and of course she denied the claim.

And while it's silly to assume Cruz, who was born in 1970, is a serial killer who has murders attributed to them going back as far as the late 1960s, the Zodiac Killer is one of those mysteries that keeps people wondering.

Perhaps it's because, to this day, it's still unexplained.

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