Very much agree with @MuslimIQ here about recording. Also, intervene if your privilege allows it. As an attorney I would have never allowed this go down this way. Anyone who can safely get in a cop's face in this situation should.
Side note for my young attorney followers: Ethics rules allow you to solicit a client directly if it's pro bono. If you see someone being hassled by authorities unfairly, walk up and say: "I'm an attorney, would you like me to be your attorney and help you free of charge?"
Every time I've done this, the person has said yes and the cop suddenly remembered he had very important things to do elsewhere.
