I feel the song is coming from an obsessive young heart. Regrettably Love that has turned to a kind of hate that took a life. Confused young soul that never felt love before keeps trying. Rather loose what little they have Ends her lovers life (no mercy)so it won't be shared with anyone else. "What have you done".
Scary thought. I could be wrong. Jealousy is a terrible thing that can get a hold of you.