If the dash lit up like a Christmas tree, and the car was towed to a garage, I would think the first thing that would be done is to
Scan the cars OBD II computer for the problem.
NB
EDIT: I happened to be in a Toyota Service Dept. today to pick up some oil filters. I asked the service manager if the
OBD II Computer can detect Water/Diesel fuel in the gas of a car that just stopped running. Apparently the codes that may appear will NOT indicate bad gas.
NB