An Indiana statute forbids drivers to use a telecommunications device (normally a cellphone) to type, transmit, or read a text message or an electronic-mail message. The statute prohibits 'texting' (sending or receiving textual material on a cellphone or other handheld electronic device; also called 'text messaging' or 'wireless messaging') or emailing while operating a motor vehicle. All other uses of cellphones by drivers are allowed. An Indiana police officer saw D driving and holding a cellphone in his right hand, that his head was bent toward the phone, and that he 'appeared to be texting.' D denied that he was texting. The officer has never explained what created the appearance of texting as distinct from any one of the multiple other-lawful-uses of a cellphone by a driver. P now concedes that D was not texting-that as he told the officer he was just searching for music. An examination of his cellphone revealed that it hadn't been used to send a text message at the time the officer saw him fussing with the cellphone. The officer pulled over D, questioned him at length, eventually asked and received permission to search the car, and discovered in the search five pounds of heroin concealed in the spare tire in the car's trunk. D was prosecuted in federal court for possession of the heroin, and though the police officer was mistaken in thinking that D had been texting, the district judge ruled that the officer had reasonably believed that D was texting. D argued that the heroin had been discovered by an illegal stop, amounting to a seizure of his person. D’s motion to suppress was denied and D pled guilty. D appealed.