How do I fight a failure to yield at a red light when the police officer himself was the "red light"?

Ok this may seem a little weird, but one day as I was driving home from school( in the U.S.) and came upon an intersection complete with a pedestrian crosswalk. A police officer was just getting out of his car that was parked on the side of the road and proceeded to raise his hand to stop my lane of traffic(I was in the right lane). I stopped of course and watched as he continued walking along the crosswalk stopping traffic as he went. Unfortunately, I thought that he was trying to cross the street using the crosswalk for some reason, so after he reached the other side, I noticed the light was still green and decided to proceed. It was only a few minutes later that the officer pulled me over. He came up to me and told me he was holding up traffic because of some "people" that were nearby, though he didn't really elaborate on it. I ume there was someone about to cross on the crosswalk that he was holding the traffic up for, though I saw no one but the officer in the road at the time of my ping. He then likened my offense to running a red light and ticketed me $185 with a court date. Now I know technically I did p through the intersection after he stopped traffic but I honestly did not know that was what he wanted drivers to do. So basically, what should I do in court? I believe I didn't really do anything wrong since I didn't endanger anyone (no one was in the road) and the officer wasn't really clear with his intentions for holding up traffic for these "people". Should I plead guilt, not guilty or give an explanation and hope the judge takes pity on me? Thanks for anyone who answers my questions.