As he spoke the final words, Doctor Palermo raised his left hand in a slight gesture. The action was seen by the man in black. Quick as a flash, he wheeled, and spread his arms apart.
He revealed an automatic in each hand. With one gun he covered Doctor Palermo. The other covered the top of the circular staircase. Hassan had appeared there, silent and grim.
The Arab was crouching for a spring. In another instant, he would have been upon his master’s foe.
The Shadow motioned with the gun that covered Hassan. The Arab understood his meaning. He crossed the floor, staring sullenly at the man in the cloak, and took his position beside Doctor Palermo. With a long, sweeping motion, The Shadow placed both revolvers beneath his cloak.
“DOCTOR PALERMO,” he said, in a deep, sinister whisper, “I have come to warn you. To warn you that you must answer for your crimes.
“You are twice a murderer; and last night, but for my intervention, you would have been responsible for a third death. But before you die — and death will be your punishment — I offer you an opportunity to clear the name of a man you have wronged, and to restore those things which you have stolen.
“In return, I shall grant you the privilege of choosing your own death, at your own hands — an easy task for a man of your scientific knowledge.”
Doctor Palermo smiled slowly. He realized that he was at the mercy of this man, yet he sought to defy him by forced bravado.
“You speak of murders,” he said, “and also of thefts. What proof have you that I committed them?”
“I need no proof. I have received a full report of Clyde Burke’s visit here last night. My brief visit to your laboratory confirmed my suspicions.