Faith didn't kill anyone. She encountered a man attacking a girl, and attempted to stop it. In the scuffle, the man was able to cut the girl's throat. The girl died in Faith's arms while she tried to stop the bleeding, and the blood plus the guilt must have triggered a breakdown.
The man has been taken care of. He's currently in police custody, and very much alive. Faith is with me. Tell whoever else you feel needs to know.