Miyu-chan wa Zutto Tomodachi - Ch. 40 - We didn't do it!

[cokelemon]

The only way I could see this end is that:

• This Miyu-chan is the twin sister of the deceased one
• Real Miyu-chan survived the encounter and even managed to fake her death somehow and is now larping as a fake one to throw off her former assailants
• A person very close to the deceased Miyu-chan and is cosplaying as her to find the culprit, even going as far as plastic surgery and such to make shit believable

If current Miyu is a reliable narrator, iirc it has already been revealed to be theory 3 (aside from plastic surgery). Her backstory was already shown and og Miyu's dad is aware of what she's doing and gave his consent iirc. I couldn't tell you the chapter numbers though, I don't remember them.