Did Watts make an improptu Dexter-style kill room [or processing room] in the basement?
We know the cadaver dogs smelled something in the basement, but whatever it was, it was a weak alert. We also know all three bodies moved through the garage and were loaded into the back of the truck. So even though we know for sure the bodies were in the truck, the cadaver dog only showed mild interest in the truck. What that shows is the bodies were well-insulated from the outside world.