There is no trace on the gambling chips- they just link this case to other cases (don't want to spoil it
)
Have you searched the tread marks in the computer- very important that you find the make of truck that made them. Also compare it to other treads you have found.
Talk as much as you can with the doctor and wife, and pharmacist.
PS: the lamp post thing might be in another case- if it is in this one, look closely at the lamp post near the area where the tire tread was- there will be a small paint chip to pick up.