My son was one of 4 occupants in a car that got stopped for speeding and one occupant had a backpack that he said was his. In it they found marijuana and papers and a pipe. There was no odor in the car and everyone checked out to not have anything in their system but they gave all occupants a ticket for drugs and drug paraphernalia except the driver? Why? Is this legal and what are our next moves? All occupants except driver were 18.