You can see it for yourself. Look up on scream wiki and click on ghostface and find casey and steve's murders. Its true that billy helped stu hang casey, but billy called casey and stu attacked. After ghostface stabbed and choked casey, she removes the mask and she recognizes the face because of her expression.
The category is only for those being see dragged/sent to Hell (or in Hell as long as they once were mortal) or become Demons not simply characters who were evil and died that way. Keep abusing/spamming it and I'll be forced to take action and block you. I don't want to but I can't let you keep just abusing it.