The Passenger's Purse

A Wyoming Highway Patrol officer stopped a car for speeding and a faulty brake light. Riding in the front seat next to the driver were his girlfriend and another woman, the passenger. During the stop, the officer noticed a hypodermic syringe in the driver's shirt pocket. Asked about it, the driver said he used it to take drugs. The officer had the two women step out, then searched the passenger compartment for contraband. On the back seat he found a purse, which the passenger said was hers. Inside was her wallet, revealing her real identity after she had given a false name, a black container holding drug paraphernalia and a syringe filled with methamphetamine, and a separate pouch she denied owning that held more paraphernalia and another syringe of methamphetamine. The officer also noted fresh needle marks on her arms before arresting her. She had not been suspected of anything before the syringe turned up. At issue: whether probable cause to search a car for drugs reaches into a passenger's own belongings found inside it.