Not filled with details, but it looks like:
Off duty cop in civilian vechicle driving home erratically/swerving into marked bike lane.
Cyclist knocks on window (with disputed amount of force, but no damage caused) to alert him to his presence.
Cop decides to abuse power because "fuck this abnoxious prick for wanting to not get run over"
Cop tells duty officer he was stopped, cyclist and witness say he was moving.
Cop tells witness he doesn't need her information/statement and that she should leave. Cyclist says she should stay.
Bystander gets witness's information and tries to give it to cyclist.
Cop tells bystander he is not allowed to give him the information, but that he will take it (what are the odds that it ever resurfaces).
Only silver lining is that it appears the Cyclist is a lawyer and the cop might not get away with this abuse thanks to witnesses. From what I can tell, he's a clerk for a district court judge.