our car hasn't been out of the garage at night for over a week."

"Perhaps Heinrich has had it out," Mrs. Cook suggested.

"I'll ask him right after breakfast," said Mr. Cook. "They must have
mistaken our car for some one else's."

"Who do you suppose sent it?"

"I'm sure I don't know," said her husband musingly. "At any rate I think
I shall turn it over to the police; I don't like the look of it."

Throughout this conversation Bob sat silent. He thought perhaps he could
explain part of the mystery to his father, but he was puzzled as to
whether he ought to do so or not. On the other hand if his father called
in the police, he knew that he and Hugh would have small chance of
clearing up the matter themselves.

"It worries me so, Robert," exclaimed Mrs. Cook. "I am so afraid that
something will happen to you, especially as you are making war supplies
at the factory now."

"The plant is guarded," said her husband. "Besides I think I owe it to my
country to help all I can, don't you?"

"Of course, but suppose some of your guards are treacherous."

"They are all trusted employees of American birth."

"No Germans at all?"