With her being able to see and hear him I wonder how much of those terrible things she said are due to her knowing the truth or seeing something terrible the others can't. Maybe she knows that it was murder but nothing else. That childhood friend does seem to have the same ability. I feel like all she wants from those murders is to have everything cute around her all the time so she kills them. A real yandere. And I feel like more is to come. We'll the cat at least
How much does she know and is trying to pretend otherwise? She was being really rude at key points there. Does she know about the psycho girl I wonder?
Taku probably think MC always bully him for all this time. That's why he curse MC to die.
Chiaki doesn't randomly kill people. Since there's not much vimtims beside these two. She must kill her close friends for something.
* theory:
Chiaki likes Taku for some reason. She kill both of them to make him happy. and she was in position to kill the girl who like MC too. it has a connection.