Thomas Horan has investigated the original police files, from which the supposed famous case of the "Zodiac Killer" was drawn. He found that the key book (and therefore all the subsequent movies, books, and stories derived from it), contained faked information.
Evidently, the "Zodiac Killer", is a non-existent character, invented by an employee of a news outlet, and attached in news stories to random, mostly unrelated murders in the San Francisco Bay area. The fabricated dramatic story definitely sold newspapers. The same methods and more are used today, by numerous media outlets, to generate fake news, and boost their circulation and revenue.