“Ah!  You are here, Mr. Blackburn!  I’d like a word with you.”

He turned to Graham and Jenkins.

“Alone, if you please.”

Bobby mutely agreed, and Graham and the butler went out.  The detective closed the door and leaned against it, studying Bobby with his narrow eyes.

“I don’t suppose,” he began, “that there’s any use asking you about your movements last night?”

“None,” Bobby answered jerkily, “unless you arrest me and take me before those who ask questions with authority.”

The detective’s smile widened.

“No matter.  I didn’t come to argue with you about that.  I was curious to know if you’d tried to see your grandfather’s body.”

Bobby shook his head.

“I took it for granted the room was locked.”

“Yes,” the detective answered, “but some people, it seems, have skilful ways of overcoming locks.”

He moved to one side, placing his hand on the door knob.

“I’ve come to open doors for you, to give you the opportunity an affectionate grandson must crave.”

Bobby hesitated, fighting back his feeling of repulsion, his first instinct to refuse.  The detective might take it as an evidence against him.  On the other hand, if he went, the man would unquestionably try to tear from a meeting between the living and the dead some valuable confirmation of his theory.

“Well?” the detective said.  “What’s the matter?  Thought the least I could do was to give you a chance.  Wouldn’t do it for everybody.  Then everybody hasn’t your affectionate nature.”

Bobby advanced.

“For God’s sake, stop mocking me.  I’ll go, since you wish.”

The detective opened the door and stood aside to let Bobby pass.

“Daresay you know the room—­the way to it?”

Bobby didn’t answer.  He went along the corridor and into the main hall where Katherine had met Silas Blackburn last night.  He fought back his aversion and entered the corridor of the old wing.  He heard the detective behind him.  He was aware of the man’s narrow eyes watching him with a malicious assurance.

Bobby, with a feeling of discomfort, sprung in part from the gloomy passageway, paused before the door his grandfather had had the unaccountable whim of entering last night.  The detective took a key from his pocket and inserted it in the lock.

“Had some trouble repairing the lock this morning,” he said.  “That fellow, Jenkins, entered with a heavy hand—­a good deal heavier than whoever was here before him.”

He opened the door.

“Queerest case I’ve ever seen,” he mumbled.  “Step in, Mr. Blackburn.”

Because of the drawn blinds the room was nearly as dark as the corridor.  Bobby entered slowly, his nerves taut.  Against the farther wall the bed was like an enormous shadow, without form.

“Stay where you are,” the detective warned, “until I give you more light.  You know, I wouldn’t want you to touch anything, because the room is exactly as it was when he was murdered!”