What I heard Lt. Chuck Mason state was: "right now she is a victim"; around the 1:00 minute mark. The key words for me is "right now". I am totally uncomfortable with Lt. Mason not wanting to comment on when BS knew of her mother's death.
http://www.wdbj7.com/news/wdbj-kidnapping-suspect-on-suicide-121710,0,10489.story
Since accounts of the state TS was in when discovered are considered rumor I shall refrain from discussing them even though those details go to this theory....that said - What if she was still alive when the person or persons, who left her that way, exited the house...badly injured and "indisposed" but not dead. Friday 12/3 to Monday 12/6 is a mighty long time to lay severly injured. That could possibly explain LE's reluctance to discuss the time of death. It would also mean that BS and JE would not have been aware of her demise until later... maybe from a newscast or radio broadcast.