I was driving near Las Vegas at around 3am. I had been following a few black SUV's along the highway for a good hour or so. They had Nevada plates that were single digit numbers in order, 1,2,3. Suddenly they all pulled off the highway down a dirt path. There was no mile marker or cactus that would indicate a path there. It was just dirt. After pulling off the road they all turned their lights off. I didn't stick around.