[ET(end tyranny)]

I also wonder if they might not be smart enough to "seed" a crime scene with spent cases from ANOTHER rifle, so that even if they get caught with a gun, they are still not tied to the crime scene.

Possible.

[Deguello]

"I also wonder if they might not be smart enough to "seed" a crime scene with spent cases"

Most likely. This is what is done in Dallas at the "Grassy Knoll" over the years. It keeps the tourist comming and the Lone Gunmen active. Pocket a few 6.5's from the gun range and drop them as you walk about. We just like to add to the equation. Everone whom then finds one thinks that they have something hot and takes it home with a smirk on their face.