"I'd like your theory then," he said dryly. "You and Mr. Paredes have both been gossiping about the supernatural. When you first came you hinted dark things. You said he'd probably died what the world would call a natural death."
"I meant," the doctor answered, "only that Mr. Blackburn's heart might have failed under the impulse of a sudden fright in this room. I also said, you remember, that the room was nasty and unhealthy. Plenty of people have remarked it before me."
Graham touched the detective's arm.
"A little while ago you admitted yourself that the room was uncomfortable."
Doctor Groom smiled. The detective faced him with a fierce belligerency.
"You'll agree he was murdered."
"Certainly, if you wish to call it that. But I ask for the sharp instrument that caused death. I want to know how, while Blackburn lay on his back, it was inserted through the bed, the springs, the mattress, and the pillow."
"What are you driving at?"
Doctor Groom pointed to the dead man.
"I merely repeat that it isn't the first time that pillow's been stained from unusual wounds in the head. Being, as you call it, a trifle superstitious, I merely ask if the coincidence is significant."