there is no pedestrian at or on the crosswalk for me to yield.

the cop's car is 55 feet in front of me and the crosswalk. that is why if they have a second cop pretend to be a pedestrian that I am not aware of.
I don't have any witness and I don't know why the cop stop me since I drive so slow and not not stop at a stop sign or run a red light.
To tell your the truth, if they did this trick in downtown Chicago crosswalk, they can get thousands of dollars a day at one intersection or crosswalk.