Had a similar situation in Australia. I was walking my bike up a hill, as I got to the top a saw the police go over the opposite way. I jumped on my bike an coasted down the hill, they, unknown to me quickly turned around and without warning or anything pulled out in front of me, jumping the gutter one onto the pathway and I only just managed to not hit the front of their SUV. They then said they are stopping me for riding without lights, I said alright I'll walk it the rest of the way. They then asked me what I'm doing riding home at this time of night, I said I'm going home from work and I didn't expect to be kept back till after dark hence not having lights. One officer said he didn't believe me and said I had been "stopped by him many times before and he had found drugs on me each time" I said "that's bullshit I've never been stopped by police", he said "I have reasonable suspicion to search your bag because I have found drugs on you before" after throwing me to the ground he removed my bag and wallet from my pocket,had the other officer place me in cuffs, then emptied the bag and wallets contents on the road and found nothing. He came across a few letters I had picked up in the mail on my way to work and because one was not addressed to me he said he will charge me with stealing and mail fraud. The other officer finally had enough I think because he said "the addresses match up and he doesn't have anything, maybe you have the wrong guy" after searching me again he gave up and drove off after threating to arrest me for "whatever I can pin on you" I was 17 at the time. Good first interaction with police...