Plot hole #1: Kill Madison. No plot hole. OR Scott Shelby is a pretty well known P.I.
Plot hole #2: Maybe the families didn't want the police to have the evidence because it showed that they committed atrocities (killing people, driving on the wrong side of the freeway) set up by the Origami Killer. Or, like most of the ones shown in-game, they don't give a fuck after their loved ones die. They don't want to help the police.
Plot hole #3: Don't get caught by the police. I didn't.
-I wonder how that scene played out. I must find out!!
Plot hole #4: Jayden's partner (I can't remember his name. I think it was Beardy McGhee) was a shitty cop. I used to be a cop. My Sgt. once deduced that a gas station robbery was committed by thieves from the north who stole cigarettes and took them back to sell. Surveillance video showed a Mexican guy who lived right next to the store as the culprit. No press release, though.
Plot hole #5: Ethan's being drugged.
Plot hole #6: AVI. Plus, the killer has an asthma attack in the middle of the fight. It's on video.
Plot hole #7: Jump out of the window, instead.
Plot hole #8: Lots of freedom when you're a cop. I didn't do drugs, but I got away with all kinds of stuff. I won't go into detail. I also know a cop's girlfriend who told me that he was a cocaine user. She said that they used it together, as a matter of fact. He got arrested for stealing gas from the department and putting it into his personal vehicle, though. Plus, who knows what the symptoms (if any)of "Triptocaine" are?
Plot hole #9: AOJ. Ability, opportunity, and jeopardy (look it up). I won't explain, but I will say that a cop in Savannah, Georgia got charged with murder for shooting a fleeing felon. Unless the guy is a prisoner in custody or a third party (or the officer) is in immediate jeopardy, it's illegal for a cop to shoot. Otherwise, I'd have shot 375 people by now. As for everybody else, who knows. Maybe they don't want to be killers.
Plot hole #10: Mad Jack didn't seem to bright. Plus, maybe that cop didn't tell anybody where he was going. Maybe he wasn't a cop but just said he was while he was trying to find the Origami Killer. Besides, how many times (in real life AND fiction) does the killer bury/hide a body inside of or under their house?
Plot hole #11: There was a dead body in that crawl space. Maybe his task was "sprinkle broken glass inside of this crawl space or I'll kill your son."
Plot hole #12: Ethan kept waking up in crazy places. He thought he had two personalities.
Plot hole #13: Some cops (I'm not claiming that I did this) confiscate guns from criminals and keep them. It's illegal as hell but it happens all the time. And Shelby is a professional killer AND a former cop. He knows how they work and what he could get away with. Plus, Kramer was dirty. He could blame the crime on Columbian drug lords or something.
Plot hole #14: Insurance money from his dead father or something? Shelby probably got a $500,000 policy for his dad and then killed him. He damn sure saved a lot of money on his mother's medication, that's for sure.
Plot hole #15: Cops look out for each other. Shelby was probably highly respected when he left. Also, why/how could Shelby clear the scene of evidence with Lauren standing right there?