In my book Mystic River,  Dave has gone into the car with the other two people that say they are cops.  After that, the other two boys went to tell the the parents that Dave had gone into the car.  Sean's Dad was very concerned for Dave.  Sean and jimmy have to talk to the real cops to tell them what the two people looks like.  The two cops came to the conclusion that they were not real cops and they were just random people.  Dave then returned to the family and was perfectly fine.  The two people did nothing to harm him.