It was Garry who introduced the subject.  “Mr. Carroll wants to ask you something about Roland,” he said softly—­and Carroll, intercepting the look which passed between brother and sister, felt a sense of warmth—­a pleasant glow; albeit it was tinged with guilt—­as though he had blundered in on something sacred.

The girl’s voice came softly in reply:  her gaze unwavering.

“What is it you wish to know, Mr. Carroll?”

The detective was momentarily at a loss.  He conscripted his entire store of tact—­“I don’t want to cause you any embarrassment, Miss Gresham—­”

“This is no time for equivocation, Mr. Carroll.  You may ask me whatever you wish.”

“Thank you,” he answered gratefully.  “You have, of course, heard that there is a woman connected with Mr. Warren’s death—­the woman in the taxicab.”

Her face grew pallid, but she nodded.  “Yes.  Of course.”

He watched her closely—­“Have you the slightest idea—­the vaguest suspicion—­of that woman’s identity?”

“No!” she answered—­and he knew that she had spoken the truth.

“You have thought of it—­of her—­a good deal?”

“Naturally.”

“Mind you—­I’m not asking if you know—­I’m merely asking if you have a suspicion.”

“I have not—­not the faintest.”

“You were quite satisfied—­pardon the intense personal trend of my questions, Miss Gresham—­that during his engagement to you, Mr. Warren was—­well, that he was carrying on no affair with another woman?”

“I say, Carroll—­” It was Garry Gresham who interrupted and his voice was harsh.  But his sister halted him with a little affectionate gesture—­

“Mr. Carroll is right, Garry:  he must know these things.”  She turned again to Carroll.  “No, Mr. Carroll—­I knew of no such affair—­nor did I suspect one.  When I became engaged to Mr. Warren I placed my trust in him as a gentleman.  I still believe in him.”

“Yet we know that there was a woman in that cab!”

“No-o.  We know that the taxi-driver says there was.”

“That’s true—­”

Hazel Gresham leaned forward:  her manner that of a suppliant.  “Mr. Carroll—­why don’t you abandon this horrible investigation?  Why aren’t you content to let matters rest where they are?”

“I couldn’t do that, Miss Gresham.”

“Why not?”

“Mr. Warren’s murderer is still at large—­and as a matter of duty—­”

“Duty to whom?  I am content to let the matter rest where it is.  All of your investigation isn’t going to restore Roland to life.  You can only cause more misery, more suffering, more heartbreak—­”

“It is a duty to the State, Miss Gresham.  And, frankly, I cannot understand your attitude—­”

“She has had enough—­” broke in Garry Gresham.  “She’s been through hell since—­that night.”

“I’m afraid, though—­”

“Mr. Carroll—­you can call it off, if you will.”  Hazel Gresham rose and paced the room.  “The case is in your hands.  You can gain nothing by finding the person who committed the—­the—­deed.  Let’s drop it.  Do me that favor, won’t you?  Let’s consider the whole thing at an end!”