JMO - Because of this Media report from the 'big dig':IMO - I’ve always wondered this, it was definitely made clear to the public that the police believed something was thrown from the car. I can only think it was the truck driver, maybe, that reported it. But what could it have been?
“Cops now believe an old hessian bag found buried in William's late foster grandmother's home could provide a clue to the boy's whereabouts.”
https://www.the-sun.com/news/4109560/bag-found-in-william-tyrrell-search/\
I wonder if such a hessian bag is believed by Rosann to have possibly been thrown from the car .....