Can I be found responsible for this one time sale of my prescription drugs?

I sold 6 of my prescribed Adderall pills in a small plastic bag to a friend as a favor. Later, he was pulled over and they were discovered in his car. Somehow my name was dropped in the encounter. The police called me to question me and wanted me to come into the station but I refused to do both. So far none of us have been charged with anything but my friend is hiring a lawyer. The police want him to cooperate to incriminate me to drop his potential charges. He does not want to do this but his lawyer may. We both deleted our text messages but if he does decide to cooperate.