Explain the movie the zodiac?!

Explain the movie the zodiac?

tell me the hold concept of it

2 days ago
Do the guy who becomes intersested with the case figures out who it is

A serial killer was commiting murders,
He send a letter to the newspaper editor saying that he will kill again if his letter was not published on that paper.
Police was hunting him down, a cartoonist was interested in solving that case,
But toward the end of the credits,....
The murderer was never caught.