Uh, oh! It's the man!

Karyn got into Jon's car with him, and they took off for the campsite. As Jon was approaching the last intersection before getting to the road that would take the to the campsite, the light turned yellow. Jon gunned the engine and went sailing through the intersection, the light turning red before he was halfway across. He immediately saw another red light come from behind him. A police car was behind him. "Oh, great," said Jon. "I didn't need this today!" The officer driving the car got out and approached Jon, who had rolled down the window. "May I see your driver's license," said the policeman, whose name tag identified him as DuMont. Jon reached into his pocket for his wallet. But, in the same pocket, was the rock.