horror manga i lost

aight so basically it’s about this opera group with four chosen girls that “adopts” orphan girls for the chance to be part of the quartet. but really they’re being used in a fucked up therapy scheme for life prisoners. one main story was about the first girl who got kidnapped and talked to herself. she lasted 8 days before dying and confessed she ripped her sisters dress. there was multiple chapters but it was uploaded as one. pls lmk if you know it i left off on chapter five and it’s killing me.