There is a videogame to be released on the 10/15 of this year titled "This is The Zodiac Speaking", related to the Zodiac case, on Steam. (a digital distribution service, mainly for the sale of video games) The story for the videogame is written by a Polish dude who is claimed in his country as the "Polish Stephen King".

Here is the official site for the game: http://zodiacthegame.com/