My list of who's going to commit murder and why.
3. Makoto - She's just been put through the mental ringer, and while she's started the road to recovery, she's far from fine. And the fact that she's just been hit with an existential bombshell that I don't believe she's processed yet puts more pressure on already shaky ground. I can see her relapsing into depression and getting dangerous now that she knows about the loops and the lack of foreseeable consequences that they give her. I believe her murder victim will be her mom. Her and Maki haven't even begun to heal their broken relationship. And I can see her snapping during an argument with her mom.
2. Ami - If you don't know why she's on the list, then you're a goober. My money's on her first murder victim being Maya. In Ami's eyes, the biggest threat to her happiness with Akira is Maya. This is hammered home in the Halloween party, where she calls out Maya, and in the bad uncle scene with Noriko. When she snaps, the first thing that's got to go will be Maya, and speaking of Maya...
1. Maya - it's impossible to miss that she's falling apart mentally. She's not mentally strong; she's just numb to it all. And her knowledge, while it didn't give her control, gave her comfort. But all that's gone out the window, new stuff is happening and her feelings that she thought she buried are resurfacing. She can't act on her feelings; she doesn't know what's going to happen, all while Ayane rubs it in her face that she has the one thing she's been wanting for the past 1000000+ loops. She's going to snap and it's going to be brutal. My money's on Ayane being her target. Ayane will probably try not to be as boastful about banging sensei after Maya's outburst at the end of the update, but since it's Ayane, she'll still do it unintentionally and consistently. Hell, I'm pretty sure if Ami does kill Maya, then Ayane's next on the list.