Can a troopers radar catch two cars doing the same speed at the same time?

I was driving ahead of my friend and didn't see him behind me, so I turned around and seen he got pulled over by a trooper. So I pulled up a ways behind them to wait on him, the trooper gave him a ticked and let him go, then he told me to pull over and gave me a ticket saying i was doing the same speed as my friend but couldn't show me on the radar.