a ship hoovered over this police car

I was hitchhiking home on Woodland Avenue in Duluth Minnesota in the late 1960’s from a friends house on a warm summer day. I was not getting a ride so I was walking on the boulevard near Hartley Field when I noticed what looked like these lights which were going around in a circle. They were red and blue. I could not see a shape yet as they were in the top of the tree line.  They hovered there for  about 1 minute when all of a sudden they started to rise slowly.  As they got above the tree line I could make out a shape which looked like two saucers laying one on top of the other. It stayed at this altitude for about another 30 seconds when all of a sudden it took off and was gone very, very quickly. I don’t remember my reaction to this as whether I was frightened or not.  I did not have much time to think about this anyway as I seen this car going very fast on this dirt road in Hartley field and hitting Woodland Avenue and without stopping sped away at a very ! high speed.  Now you would have to see how dangerous this can be as the dirt road is a steep hill and when you got up to Woodland  Avenue there was a stop sign because it is in the middle of a sharp curve and you don’t just run this stop sign without looking both ways.  As this car sped away I noticed that it was a police car! I thought wow here this police car had come out of Hartley field right where the ship was hovering!  I did not have much to to think about this though as a friend picked me up and asked if I had seen this. I really do not remember anything else we said, and I never really talked much about this. I think I was afraid that no one would believe me. I always wondered though if those two policemen filed a report or told anybody as it was plain to see that they seen this.
Witness indicates that date is approximate.  PD