"Thank you," said Walter Crocker shortly.
He climbed into the car and drove away.
"That's a good one!" laughed Penny, highly amused. "He has lost the Crocker letters all right, and he thinks they may be in our car!"
"Don't you expect your father home before night?" asked Susan.
"Of course I don't know exactly when he'll come," chuckled Penny. "But I'd not be surprised to see him driving in any minute. I wanted to give myself plenty of time to examine the car before Mr. Crocker returns."
"What would you do if you found the letters, Penny?"
"I haven't thought that far," Penny admitted. "But the chance that they're in our car is a very slim one."
The girls stationed themselves on the front porch so that they would not miss Mr. Nichols when he drove in. Two hours later they glimpsed the car coming up Knob Hill.
Penny meant to tell her father everything that had happened during the day, but the detective seemed to have important matters on his mind. When the girls ran down to the car to meet him, he responded absent-mindedly to their greetings and went on into the cottage.
"Penny!" exclaimed Susan. "There's another auto coming up the hill!"