“It looks foxy to me,” growled Cardona. “Briggs was mixed in it; but it’s so dumb it looks foxy.
“All the deaths before this were cleverly hidden. This one — straight to the source.”
“Don’t forget,” declared Biscayne, “that if the bomb had exploded, this would not have been so easily traced.
“If there had been a mysterious explosion at Arthur’s house, the chief evidence — the bomb itself — would have been destroyed.”
“The trail would have led here, anyhow,” persisted Cardona. “Packages would have been the first thing to ferret out and trace down. That bomb was charged heavily enough to blow up only one room — not an entire house.”
There was a long, deliberate pause. Roger Biscayne was thoughtful, considering deeply.
His eyes began to glow. His hand was moving up and down. He was preparing to speak. But Cardona anticipated him.
“We’ve got to hunt here,” said the ace detective. “This place is phony. That letter that was mailed here tonight—”
“Wait!” interrupted Biscayne. “It’s clearing in my mind! The final death — tonight. Why should the murderer worry about covering it up?
“His work was ended, by his own admission. The fifth death, and the last!”