I'm a new poster and didn't see this thread back when it occurred.
I'd like to parse the half-sister's comments about the cats as that is kind of curious to me. It was a very quick and easy answer as to why the house, normally locked up, might be unlocked when someone was down in the *surprise where the body was found* laundry.
I think that ready answer, even though people haven't pointed to it specifically, is why people early on considered her as a suspect.
She states something to the effect of the door is normally locked except when someone is down doing laundry. It's open because the we have an ornery cat who can open a door.
I think the sister is using "open" in the first instance to really mean unlocked. And they have an ornery cat who can open the door while you are down doing laundry. So, is the cat ornery because it can open the door, while no one is around and escape, or is it ornery because the cat can move the door, in effect, really closing it while someone is downstairs and if the door is locked, you get locked out if you don't have your keys?
Does all that make sense? It's a ready story for why a door, normally locked is really unlocked (i.e., open). If the cat can really open a door, and some can paw a slightly ajar door to open it, then the cat is ornery because it escapes from the house. If the cat actually closes the door while you are downstairs, you make sure it is unlocked so you don't get locked out.
To me, she doesn't actually explain the cat v. door open situation very well in her first interview. But, it was readily given up, maybe even prepared, to have a reason why the door might be open, i.e., unlocked, especially since the sister was found in the laundry which gives an easy explanation that someone came in on her while she was doing laundry and thus the unlocked door.
And it is interesting the type of DNA they are searching for, if there are prints on the bag with similar DNA but different mito DNA, a sibling might be involved.