The Secret of the Old Mill by Franklin W. Dixon Page A

license number, which Mr. Hardy said he would report to Chief Collig at once.
    When Mr. Hardy returned from the telephone, he told the boys the chief would check the license number with the Motor Vehicle Bureau in the morning and by then he also would have some information about the print on the archer’s finger guard.
    The next morning after breakfast Frank said he wanted to take another look at the warning notes.
    â€œWhy?” Joe asked curiously as they went to the file.
    Frank held up the “arrow” warning, and the one received by Chet. “I’ve been thinking about the printing on these two—seems familiar. I have it!” he burst out.
    â€œHave what?” Joe asked.
    â€œThis printing”—Frank pointed to the papers —“is the same as the printing on Ken’s envelope addressed to Victor Peters. I’m positive.”
    Excitedly the brothers speculated on the possible meaning of this clue. “I’d sure like to find out,” said Joe, “who addresses the envelopes Ken delivers, and if they’re always sent to Mr. Peters in the Parker Building. And why—if he doesn’t have an office there. And who is Victor Peters?”
    â€œIf the person who addresses the envelopes and the sender of the warnings are the same,” Frank declared, “it looks as though he’s sending something to a confederate, under pretense of having work done for Elekton. I wonder what that something could be?”
    â€œAt any rate,” Joe added, “this could be a link either to the counterfeiters or to the saboteurs. Which one?”
    The boys decided to go out to the mill again, in hopes of quizzing Ken Blake. Just then their father came downstairs. Frank and Joe were glad to see that he looked rested and cheerful.
    Mr. Hardy phoned Chief Collig. When the detective hung up, he told his sons that the license number belonged to stolen plates and the fingerprint to a confidence man nicknamed The Arrow.
    â€œHe’s called this because for several years he worked at exclusive summer resorts, teaching archery to wealthy vacationers, then fleecing as many of them as he could. After each swindle, The Arrow disappeared. Unfortunately, there’s no picture of him on file. All the police have is a general description of him.”
    Frank and Joe learned that the swindler had a pleasant speaking voice, was of medium height, with dark hair and brown eyes.
    â€œNot much to go on,” Joe remarked glumly.
    â€œNo, but if he is working for Elekton, he must be pretty shrewd to have passed their screening.”
    Mr. Hardy agreed, and phoned Elekton, requesting the personnel department to check if anybody answering The Arrow’s description was employed there.
    The brothers then informed their father about the similar lettering on the warnings and Ken’s Manila envelope.
    â€œA valuable clue,” he remarked. “I wish I could go with you to question Ken.” The detective explained that right now he had to make his report of the explosion to the nearby FBI office.
    When he had left, Frank and Joe rode off to the mill on their motorcycles.
    At the gatehouse the guard had unexpected news. “Ken Blake isn’t working here any more,” Mr. Markel said. “We had to discharge him.”
    â€œWhy?” asked Joe in surprise.
    The guard replied that most of the necessary jobs had been done around the mill grounds. “Mr. Docker—my coworker—and I felt we could handle everything from now on,” he explained.
    â€œI see,” said Frank. “Can you tell us where Ken is staying?”
    Markel said he was not sure, but he thought Ken might have been boarding in an old farmhouse about a mile up the highway.
    When the brothers reached the highway, they stopped. “Which way do we go? Mr. Markel didn’t tell us,” Joe said in chagrin.
    â€œInstead of going back to find out, let’s ask at that gas station