note that had been left at the door that afternoon.
"Some one left a letter for you this afternoon," she said. "I heard the doorbell ring, but when I went to answer it there was no one at the door. I picked up a letter, though, and I put it on your study table."
Fenton Hardy went into the study and picked up the letter, slitting open the envelope. Within, was a thin sheet of cheap paper on which had been written a few lines in pencil.
He read the message with a slow smile, then handed the paper over to his wife.
"Some one trying to scare me," he said.
She picked up the note. In a crude, ill-formed hand, she read the following:
"Better give up this counterfeit case or we'll take the shirt off your back. We know this game too well. Let this be a warning to you. Poor Blum is a rank outsider. Better let him go."
Mrs. Hardy looked up anxiously.
"What are you going to do about this note?" she asked.
The detective shrugged.
"Ignore it, of course."
"But they may harm you."
"They may try. They won't be the first
