> I don't think he originally wanted to leaved her body in the house. IMO, I think he reacted in panic

Ditto to that.

You know, I was reading a portion of PMPT (paperback) in which Schiller says the woman - Melody Stanton? - who originally heard the scream on the night of the murder was getting nervous and her statement was beginning to wobble. (Not a quote - paraphrasing.) Masked Man's later interview with her notwithstanding, I still think she heard a scream the night of the murder, and, I believe as far as the perp was concerned, that scream was not supposed to happen. I would imagine he thought that a stun gun would paralyze a victim, just as most of us did before getting an education in stun guns.

The scream would have been the source of the panic, just like most of us thought years ago. He dropped what he was doing and left, dragging the body out of sight in case someone came flying down the stairs to investigate. A quick, vicious head blow for insurance, and he was gone.