What finally turned me was Ashton's description of the APPLICATION of the duct tape. Three pieces, very deliberately placed...across the mouth, then one each at a 45 degree angle to cover each nostril. Before I thought there was at least a possibility that the duct tape had been applied post-mortem to stem the flow of bodily fluids. However, I truly think if that were done there would be a lot more tape applied and in a more "round and round the face" fashion. I also suspect coming in rebuttal will be discussion of the "heart-shaped" sticker residue placed OVER the duct tape...Casey's final goodbye to her "favorite pet."
So I've now been convinced. Murder one, malice aforethought.