“Not far. He has an office and laboratory in the Waldmere Chambers.”
“H’m, is that so? Who is he?”
“Professor Karl Graff.”
“Humph!” Nick ejaculated. “I remember him.”
He now recalled for the first time, in fact, the elderly man who had approached from the rear of the corridor in which the corpse of the mysteriously murdered Gaston Todd was lying. He remembered the negative statements this man had made. He recalled, too, Patsy Garvan’s description of the gray-bearded man seen at Leary’s road house and the mysterious killing of Leary’s cat. All this flashed upon him with sudden startling significance, giving color to the physician’s story—though Nick decided to keep an eye on him.
“That’s a good idea,” he said abruptly. “Get ready at once. We will go together and see him.”
Doctor Devoll complied with alacrity. A leer lurked in his eyes when he hastened into his bedroom. He quickly returned, wearing his black frock coat and tall silk hat.
“Now, Mr. Carter, I am ready,” he said, smiling. “I will speedily set myself right in your estimation.”
Nick had convictions to the contrary, but he did not express them. In reality, nevertheless, he was considerably puzzled by the increasing complications, and he began to suspect that Professor Karl Graff might be the guilty man, after all—the discoverer of the potent narcotic that had made possible the long series of mysterious crimes.
It was ten o’clock when they entered the Waldmere Chambers and hastened up to the second-floor corridor, toward the rear of which Doctor Devoll conducted the detective, remarking agreeably: