We would need to know more facts, including the officer’s reasoning for the search, to determine if the search was valid. But let’s start here: was the driver arrested for DUI prior the search being done? If so and the car was going to be impounded due to the arrest then search would be lawful as an inventory search of the car. The persons facing drug charges need to ask their attorneys whether there may be any basis to suppress the evidence found based on the search.

