Maybe I’m just face-blind or being dense but the photos from the scene of the crime look like a different dude than the ginning hostel check in guy. The jackets and backpacks are different. Although people can have multiple jackets and backpacks. We don’t see much of the shooters face but the eyebrows look different. Although, people can pluck/shave eyebrows. I guess the happy hostel guy would have come forward and been like “WTF?” and “I have an alibi” if it wasn’t him?
If happy dude isn’t the CEO clean up guy, walking into a police station would be the best to way to ensure he gets the CEOs death pinned on him or worse. Happy dude would be best hiring a lawyer and following their advice.
Assuming he was elsewhere on CCTV at the time of the shooting (work, university, cafe) he should be ok.
Something I’ve learned in life is that should be and is are not the same thing. You’re right, that he should be okay, but the cops are going to want to stick this to someone. It’s way too high profile for them to let it go. If happy dude isn’t their guy and walks in the front door, the cops would make him their guy.