It won't matter who it is, they'll all pick on the dead ones. Sorry for images, but dead meat is food for them no matter what or who it used to be. Even if you feed them, they'll keep eating.
I don't think one girl killed another, you would have seen the aggression even if it was flipped on a dime, that one would still be aggressive to others now. So it looks like your girl died of unknown causes and then the girls just ate from there. :-/
RJ (H. Lifalili), Acara (EB)
Ghost, Tuxedo, Trip (Angels)
Leopards: 1:3 Hawkeye, Luna, Astrael, Dorian