I think you’re sort of half-right: Some circumstantial evidence points to KR at first blush. There is other circumstantial evidence that does not. For instance, she spent hours with Faith earlier in the evening and then went out to the club with her; if there was some incipient conflict between them, would they really have done that? Also, the two of them willingly left the club together to go home; it should go without saying, but if Karena had gone off on Faith and screamed “I’m gonna kick your face, b****!” like she supposedly did in the pocket-dial transcript, I doubt Faith would have given her a ride home 45 minutes later. She probably would have gone to stay with another friend.
Even some of the seemingly suspicious circumstantial evidence gets less so if you really look at it. Like her leaving the apartmentat 4:30 AM. A lot of people look at that and think she’s fleeing a crime scene. But if it looks like that to us, it obviously looked like that to LE too. She had to have told them her reasons for leaving, and LE would have checked her story out with JM and probably MR too (who presumably heard something about it on the way back to the apartment the next morning). The fact that LE knows all of that and still says that KR isn’t a suspect can tell us something.
I also don’t see why it follows that she knows more than she’s saying. Everyone that could have committed the crime that she has some obvious attachment to has been checked out, and I can’t see why she’d be denying justice for a good friend of hers for someone she only kind of knows. She’s not part of the mob or some gang with a “no snitch” culture, and we’ve been told over and over again that she’s been cooperative with the police.
I really think she’s a dead end.