“I have to be at home,” said Wilhelm. “But give me a ring if you uncover anything. This sounds interesting to me.”

“Tonight, then,” announced Cardona, rising. “We’re going back to first base. Right where the trouble started.

“I’ve got a hunch that we’ll hit something big. One real break — and we’ll win!”

“The old man knew a lot,” said Biscayne thoughtfully. “He had his secrets, and he retained them. I’m thinking now — recalling his queer talk of enemies.

“I agree with you, Cardona, that a good find will clear every cloud that has formed.

“Harshaw’s enemies — and Harshaw’s plans,” continued Biscayne, in a low voice. “In his head. I can hear the old man talking now. Did he ever speak that way to you, Fredericks?”

“Not often,” replied the physician. “Our discussions usually concerned his physical condition.

“But I believe that the proper suggestion might arouse some recollection in my mind. I shall be there this evening, professor.”

“Yes,” said Biscayne, “tonight is most important. We shall do our utmost to end this chain of murders.”

CHAPTER XVIII