My understanding is that one of the forms of identification that the officer was shown was a Harvard ID. The professor's name would presumably have meant nothing to the cop, but the university name would have meant something to him.

I know that in many places, the town has a grudge against the university, especially when the university is a private, elite one (Duke, for example). If my supposition about the cop's background is accurate, I can easilly imagine him thinking "I come here on a call, doing my job, and you think you can berate me because you're a big Harvard man? Fuck you!"