This is my first thread, so please be kind and feel free to delete if you feel it's repetitive, but I got to thinking this would be nice to see all thoughts!
For me, I don't think it was butter knife that was in the car. We have CA's word on that, I think it was a sharper knife to cut duct tape. Thus, I also think of course they are looking for duct tape and garbage bags as well.
I also think they are collecting fibers from the carpet in the house, as those would again most likely be caught on the duct tape.
You started a very good thread for your first! I was also curious to read this morninng that they took vacumns with them, not just the bags, and a thing you use to spray for bugs! I can't remember the name of it.
They have some good reason to believe that Caylee was killed in that house.
I always assumed that when she left after the fight of June 15th, she took Caylee, or came back for her early in the morninng, and killed her somewhere outside the home.
Good post.