I just can't quite get past the thought that, as little forethought as was seemingly given to the planning of this murder, I just have this strong feeling that her killer was familiar enough with her home that he knew there was a duffel bag there big enough that he could shove her body into it and get her out of the house unnoticed (except he didn't take into account he would leave a trail of blood leading back to her house), and he knew he could strip off his bloody clothes and there would be clothes there he could change into, seemingly including shoes that would fit well enough he could walk normally in them, and he knew where to find them and how to get them without being seen by the son upstairs. I think it is also entirely possible, and maybe even likely, that he used one of her own kitchen knives to kill her. I don't really think he took anything with him, and may not have even been planning to kill her in the beginning, but something quickly took a terrible turn, and everything beyond that was done, flying by the seat of his pants. JMO