Dale had failed with the Doctor.  When Lizzie’s screams once more had called the startled household to the living-room, she knew she had failed.  She followed in mechanically, watched an irritated Anderson send the Pride of Kerry to bed and threaten to lock her up, and listened vaguely to the conversation between her aunt and the detective that followed it, without more than casual interest.

Nevertheless, that conversation was to have vital results later on.

“Your point about that thumbprint on the stair rail is very interesting,” Anderson said with a certain respect.  “But just what does it prove?”

“It points down,” said Miss Cornelia, still glowing with the memory of the whistle of surprise the detective had given when she had shown him the strange thumbprint on the rail of the alcove stairs.

“It does,” he admitted.  “But what then?”

Miss Cornelia tried to put her case as clearly and tersely as possible.

“It shows that somebody stood there for some time, listening to my niece and Richard Fleming in this room below,” she said.

“All right—­I’ll grant that to save argument,” retorted the detective.  “But the moment that shot was fired the lights came on.  If somebody on that staircase shot him, and then came down and took the blue-print, Miss Ogden would have seen him.”

 He turned upon Dale.

“Did you?”

She hesitated.  Why hadn’t she thought of such an explanation before?  But now—­it would sound too flimsy!

“No, nobody came down,” she admitted candidly.  The detective’s face altered, grew menacing.  Miss Cornelia once more had put herself between him and Dale.

“Now, Mr. Anderson—­” she warned.

The detective was obviously trying to keep his temper.

“I’m not hounding this girl!” he said doggedly.  “I haven’t said yet that she committed the murder—­but she took that blue-print and I want it!”

“You want it to connect her with the murder,” parried Miss Cornelia.

The detective threw up his hands.

“It’s rather reasonable to suppose that I might want to return the funds to the Union Bank, isn’t it?” he queried in tones of heavy sarcasm.  “Provided they’re here,” he added doubtfully.

Miss Cornelia resolved upon comparative frankness.

“I see,” she said.  “Well, I’ll tell you this much, Mr. Anderson, and I’ll ask you to believe me as a lady.  Granting that at one time my niece knew something of that blue-print—­at this moment we do not know where it is or who has it.”

Her words had the unmistakable ring of truth.  The very oath from the detective that succeeded them showed his recognition of the fact.

“Damnation,” he muttered.  “That’s true, is it?”

“That’s true,” said Miss Cornelia firmly.  A silence of troubled thoughts fell upon the three.  Miss Cornelia took out her knitting.