After reading the latest Mr Burner depo. Where he retrieved the shovel from his shed.
Since we know Casey couldn't get access to George's shed gas, or Cindy's bank account, is it possible ICA didn't want the shovel at all, but simply a look-see inside His shed for GAS? It seemed quite silly to dump your murdered daughter right around the corner from her house. Did Casey not have enough gas to drive around finding the perfect hiding spot grave? Did Mr Burner 'thwart' her gas stealing idea by locking his shed after fetching his shovel?
She didn't look sweaty or dirty from using a shovel. The shovel looked in almost mint condition from when he loaned it.
Just a thought