This chapter will be available if Jayden survived Fish Tank. You'll be in your office, at a seeming dead end in the investigation, when Blake comes in to tell you you're through. If you didn't turn off the camera during Under Arrest, he'll say you're getting suspended for it, and otherwise (if you did turn it off or Ethan never got arrested) he'll just say they don't need you anymore, since he figured out Ethan is the Origami Killer. When he leaves, you'll take one last crack at putting the pieces together to save Shaun and clear Ethan's name. If you haven't been resisting your drug urges, you'll take a little bump first and the virtual butler will give you another warning before you start.
You can quit at any time out of ARI from the main menu. When you do, you'll be given the option to continue or give up. If you give up you'll take whatever heat's coming to you for failing to solve the case, and you won't get a chance to save Shaun. If you don't want to give up, look in your clues for some new evidence. You'll see that ARI was recording during your fight with the killer at Paco's office, and you'll also see the receipts that were in his torn pocket if you got them at the end of the fight. If you also found the killer's gun at Paco's place, that will be the last piece of new evidence. All you need to solve the puzzle are the receipts and the video.
Open the video and start playing it by pressing . You can pause at any time by hitting the same button, or set the direction of playback with and . Pause the video and analyze it with . In the second half of the video, you'll find the useless clue of the samurai sword. Rewind and analyze somewhere in the first half to get a good clue: the gold wristwatch. You'll remember that the watch is given to cops when they become lieutenants, so you'll figure out that the Origami Killer is or was a policeman. A new clue in the form of a question mark will be added to ARI. Close out of the video by tugging down on the controller.
When you analyze the new question mark clue, you'll know it's a cop and that Blake fits the profile. At this point you can accuse Blake or investigate further. If you accuse Blake, you go out to his desk and confront him. You'll get a couple opportunities to back down from your claim, but if you persist, you'll eventually draw your gun on him and put him under arrest. This will result in you having a mental breakdown and Captain Perry chewing your ass.
If you continue to analyze clues, you can do a geoanalysis on the question mark to throw all the locations of cops in the Origami Killer's safety zone up on the map. When you cross-reference those police officers with the geoanalysis from the gas station receipts, you'll have enough to pinpoint the one cop in that area and discern the killer's identity. Before you do that, you'll want to analyze the gun you found at Paco's so you can still get the Nerd trophy. Once you've found out who the killer is, you'll head to a warehouse he owns. You must do this quickly, as if you spend too long Jayden will die. If blood starts coming out of his eye, that's your cue to hurry up!