"Detained", as in "prevented you from continuing about your business".
I got a "Hey, you with the pistol! Come here a second!" from a cop in Home Depot once.
I simply replied, "No thanks, officer. I don't need any assistance." and kept walking.
Oddly enough, he didn't follow.
I was fully prepared for him to do so, however. If he wanted to reiterate his desire for a conversation, I was ready with the verbal refusal for any further voluntary interaction with a closely followed, "Am I being detained?", but fortunately, it wasn't necessary.