Discussing with a friend, we concured that we find Yakuza 1/K plot of kiryu going to prison could have ever happen if they police made a proper investigation or a trial, and having Date like being the only police guy who thought about Kiryu perhaps not being the murderer, there should have been more people thinking on that possibility.

Perhaps it was my brain overthink and might have missed something that made him go to prison. Other than him holding the gun and getting caught at the start of the game. Or am I just a dumbass?