This may or not be worthy for it's own post, but someone had stated previously in the main thread that perhaps NO ONE called him from the office when she was late to work (consciousness of guilt), and that he (1) spared his mother of the horrific scene and (2) knew that her/their doctor friend would swing by to be able to handle the scene. The doggy door is interesting to note as is the lanai door "propped open," and I'm not sure what that means either. I guess more evidence of staging? I'm thinking BS (Mark's mom) could say for sure whether or not the plastic on the doggy door was removed and/or the door was propped open. She remembered leaving and/or seeing things in the kitchen (protein drink thing, or something?) which was corroborated by LE.
ETA: My SIL was once suspicious of her husband, and she showed me years ago how she could track him on line using his ?Verizon? phone. It was a service that you paid extra for at the time, but it might have changed now. Anyway, she knew how to use it, was sorta proud of the fact and let me in on the sordid details. I think Mark probably knew too how to use the tracking programs.