Some buffer images in case you accidentally clicked on this, the guide is just below them.
Investigation
In general, the investigation is a very basic "exhaust talk options and then move when prompted" type of deal, but here are the exact steps.
Detention Center: Select the talk topic "You said destruction of property, right?" and then the talk topic "Can you tell me about the arrest?". Once you're done with that, you can
move to the Apartment Building. Go ahead and do that.
Apartment Building: Choose the "What can you tell me?" talk topic, then the "Where did the other two go?" talk topic. This will give you access to Cecil and Lynette's Room.
Move there.
Cecil and Lynette's Room: Choose the "What happened, from your point of view?" talk topic. After that, select the "Do you have any questions for me?" talk topic. Marnie will mention that she should talk with Liese after that, so move back to the Apartment Building and then move to the Detention Center.
Detention Center: A new talk conversation called "I've finished my investigation." will have unlocked. Select that, then confirm your choice (you're given the option to back out in case you want to hunt for more optional dialogue).
Note: The investigation has unique dialogue for every piece of evidence and profile that you can acquire during it for everyone you can talk to. Examining a location will bring up a menu of four options of what Marnie should do. This is all optional and you don't need to present or examine anything to continue, but I encourage reading as much as you can/want to.
Trial
Note: During each testimony, there's a unique conversation for presenting the Attorney's Badge on any statement, as well as a separate unique conversation for presenting the Yuya Merch on any statement. These change with each testimony.
CE1: Press all of Sydney's statements.
CE2: Present the Earbuds or Lynette's profile on statement 5, 6, or 7 (any of them work).
- Choose "The earbuds you were wearing before were noise-canceling", though you can choose any of the other two options and it'll loop you back to pick another choice.
CE3: Present the Cough Medicine on the fifth or last statement.
- You can choose either option on the follow-up question, though "It's about the listed side effects..." is the actual correct answer.
CE4: Present the Script on the fifth statement.
CE5: This CE has the most possible potential ways of proceeding through it, though they all lead to the same outcome.
Option 1: Present Lynette's Letter, the Superpower Analysis, or the Destroyed Camera on Dieman's second theory.
Option 2: Present Lynette's Letter, the Superpower Analysis, or the Destroyed Camera on Lynette's statement.
Option 3: Go to the end of the theories, select "I could come up with my own theory..." and then present Lynette's Letter, the Superpower Analysis, or the Destroyed Camera.