The Mystery of a Boy Who Walked Into Sand Hills With Schoolgirls

When Christine and Marianne didn't return, the other children left on their own. They boarded a train and headed home. Wolfgang later admitted that the boy seemed angry when he came from the sand hills. This is strange. Did helmet think his sister and Christine just wandered off and then would return on their own? It's unclear. And there was no mother or father at the house to worry and alert authorities. So who called the cops? Christine's grandmother, the one who was so adamant that Christine not go to Crannell Beach without an adult.