If police pull you over and tell you you're free to leave, they need reasonable suspicion to conduct a second round of questioning. In Commonwealth v. Nguyen, a trooper initiated a traffic stop on the defendant for speeding. The defendant refused to answer any questions but eventually provided his license and registration. When his license was run, the trooper learned that the defendant had prior drug arrests. He then issued a warning to the defendant for speeding, returned all information and told him he was free to go. However, as they walked to their respective vehicles, the trooper turned and re-engaged the driver by asking if he could question him further. The trooper then asked if he could search the car and its contents and the driver consented.

The defendant was asked to step out of the car and agreed to be frisked for safety purposes. During the frisk, the trooper felt a soft package in his front pocket that he believed contained bagged pills. When he asked what it was, appellant said it was OxyContin. During the search incident to arrest, troopers recovered 3 bundles of cash, 4 bags of cocaine and 4 jars of cocaine. The defendant argued that this frisk was not supported by reasonable suspicion.

The Superior Court held that once a police officer concludes the business of a traffic stop, but then re-engages the driver for questioning, that this constitutes a second, separate detention and must be supported by reasonable suspicion.

The information the trooper had about the defendant's prior drug arrests could not support a finding of reasonable suspicion, as the officer was aware of these facts before telling the driver he was free to leave. The court further held that the defendant's actions of being overly-apologetic, nervous and talkative were insufficient to establish reasonable suspicion to support the second round of questioning.