“Beresford,” commanded the detective, “take Bailey to the library and see that he stays there.”

Beresford tapped his pocket with a significant gesture and motioned Bailey to the door.  Then they, too, left the room.  The door closed.  The Doctor and the detective were alone.

The detective spoke at once—­and surprisingly.

“Doctor, I’ll have that blue-print!” he said sternly, his eyes the color of steel.

The Doctor gave him a wary little glance.

“But I’ve just made the statement that I didn’t find the blue-print,” he affirmed flatly.

“I heard you!” Anderson’s voice was very dry.  “Now this situation is between you and me, Doctor Wells.”  His forefinger sought the Doctor’s chest.  “It has nothing to do with that poor fool of a cashier.  He hasn’t got either those securities or the money from them and you know it.  It’s in this house and you know that, too!”

“In this house?” repeated the Doctor as if stalling for time.

“In this house!  Tonight, when you claimed to be making a professional call, you were in this house—­and I think you were on that staircase when Richard Fleming was killed!”

“No, Anderson, I’ll swear I was not!” The Doctor might be acting, but if he was, it was incomparable acting.  The terror in his voice seemed too real to be feigned.

But Anderson was remorseless.

“I’ll tell you this,” he continued.  “Miss Van Gorder very cleverly got a thumbprint of yours tonight.  Does that mean anything to you?”

His eyes bored into the Doctor—­the eyes of a poker player bluffing on a hidden card.  But the Doctor did not flinch.

“Nothing,” he said firmly.  “I have not been upstairs in this house in three months.”

The accent of truth in his voice seemed so unmistakable that even Anderson’s shrewd brain was puzzled by it.  But he persisted in his attempt to wring a confession from this latest suspect.

“Before Courtleigh Fleming died—­did he tell you anything about a Hidden Room in this house?” he queried cannily.

The Doctor’s confident air of honesty lessened, a furtive look appeared in his eyes.

“No,” he insisted, but not as convincingly as he had made his previous denial.

The detective hammered at the point again.

“You haven’t been trying to frighten these women out of here with anonymous letters so you could get in?”

“No.  Certainly not.”  But again the Doctor’s air had that odd mixture of truth and falsehood in it.

The detective paused for an instant.

“Let me see your key ring!” he ordered.  The Doctor passed it over silently.  The detective glanced at the keys—­then, suddenly, his revolver glittered in his other hand.

The Doctor watched him anxiously.  A puff of wind rattled the panes of the French windows.  The storm, quieted for a while, was gathering its strength for a fresh unleashing of its dogs of thunder.