I know a popular theory for some is that SM & TM hung on to H.E's body for a week or more and then moved her somewhere for disposal. And while that's an interesting theory, I really can't imagine them carting a body around. Dead bodies, unless preserved, start to decompose and it would be apparent within 48 hrs or less. They had no idea when police might show up; as it turned out police first made contact 12/20 or 12/21. I don't see them storing a dead Heather for further movement. I believe H.E. was disposed of within hours of her killing.
I totally agree with this. I think they had a plan to quickly dispose of her body, and sadly, it worked.