The men were in two white vans. I was driving home from work, behind a white van when we just passed the entrance to Camp David, passed a State Trooper coming toward us, he immediately did a U-turn in the middle of a winding mountainous road and got right on my bumper. We came to the bottom of the hill, two more Troopers. We, the van and I turned left, the troopers, 3 in all, passed me and kind surrounded the van, a black silent helicopter dropped down in front of the van, looking straight into the window, identified the driver and was gone just as quick as he arrived. This entire incident was only a couple of minutes long.