The Real Killer
I figured out that the asian woman was 'the killer' about halfway through the series - when they revealed that she had been living in san vicente for a year. But I kept thinking that it was so obvious it had to be a misdirect. Here's my theory:
The real 'killer' is the mayor. He keeps banging on about how getting a big modern employer like Brooks Industries into town was his legacy that he'd been working on for 20 years. And he demonstrates that he's willing to do basically anything to make it happen. So he hired the hooker to seduce coma boy in order to convince him to sell to Brooks as incentive to bringing Brooks to san vicente. Coma boy rented that apartment to tryst with the hooker (who he didn't know was a hooker since the mayor was paying her) after all asian girlfriend had her own place, she didn't need a secret sex apartment.
In the hotel lobby, when the judge's wife threatens the hooker, she makes a big deal about how she only has a couple of rules about who she will have sex with and doing the father and the son wasn't on the list of no-nos. Also it is pretty odd that the mayor is so congenial with the hooker, even if she was the judge's (paid) mistress, that scene where she just walks in to his office and starts negotiating for her mother's house. They were obviously on good terms. That's not normal even for a high-priced escort.
When coma boy wouldn't sell to Brooks, the mayor blackmailed the cop to steal the USB drive to give to Brooks as a bribe. After all it makes a lot more sense that the mayor would have leverage on a beat cop than a corporate acquisitions person would.
The asian woman was just a regular girlfriend who stole the book after the cop had already taken the USB drive. She never said whether coma boy dumped her before or after the rape. It makes more sense he would dump her after his wife was raped since he'd be feeling really guilty about carrying on with a mistress after that happened to his wife. She never admitted to stealing to the USB drive, all the talking about that was so ambiguous as to be contrived.
Also the hooker is pregnant with coma boy's kid, not the judge's kid. For all we know, the judge is shooting blanks since he was never able to conceive a 2nd child with his wife.