"You're gonna catch him...... Pal, they're already making movies about it"

it's Arthur Leigh Allen. periodt

-He has the Zodiac watch (the one that the killer based his symbol + name of)
-his favorite book/movie was the same that the killer quoted in one of his letters.
-A social worker said that he thinks that Arthur is capable of killing people.
- same size shoes AND gloves as the killer
- he was born on the !!!!!18th!!!!! of december