Would you care to hazard an opinion regarding her likely circumstances?
What I am trying to say is that in this case ( and in any other) you cannot make firm conclusions.
I tend to trust physical evidence more than any 'theory'.
There is no proof anyone died in that apartment.
She might have recognised the intruder who might have had been working there and performing a role of a good law abiding citizen. She even might have been taken for order by telling a drug user 'give us a child, we give you drugs'.. or if she accidentally died in that apartment IMO it is impossible that the cadaver scent was developed there.
The police has to work by eliminating and this is exactly what they do.. So one week we hear it is the ex OC workers. the other week we hear other news, IMO this is just the police working on certain clues and eliminating them.
What they definitely have are the phone records. So they might have a handful of people in mind who happen to match the phone masts areas.
If any of them left the area the day after this would be the most alarming. Like this tractorman who was reportedly signed off work in the following days.. this is why they suspect him.. etc etc..