Originally Posted by
sggoodri
I would first ask the police what they want. The could be looking for witnesses as part of a crime investigation. I would be happy to help.
If their attention was on me, and not how I could help them, and they seemed to be fishing, I would frankly ask them if I was free to go.
Your approach is perfectly reasonable, and leaves no question to weather or not the stop is considered a seizure under the fourth amendment.