“Please—­don’t think that!”

“What?”

“That is was—­was my husband.  He wouldn’t—­”

“Why not?”

“Anyway—­it is impossible.  He was in Nashville.  He didn’t get home until morning.”

Carroll shook his head.  “I hope he can prove he was in Nashville.  We have tried to prove it, and we cannot.  And you must admit, Mrs. Lawrence, that had he known what you planned he would have had the justification of the unwritten law—­”

Her eyes brightened.  “You think, then—­that if he did—­he would be acquitted?”

“Yes.  More so in view of your story that there was a fight between the two men.  That would probably add self-defense to his plea.  However, I may be wrong in that—­”

“You are indeed, Mr. Carroll.  My husband—­isn’t that kind of a man.  And even if he had done the shooting—­he could not have concealed it from me for this length of time.  He would have given a hint—­”

“No-o.  He wouldn’t have done that.  If he shot Warren he would have been afraid of telling even you.”

She walked to the window where she stood for a moment looking out on the drear December day.  Then she turned tragically back to Carroll.

“You are going to arrest me?”

“No.”

“Why not?”

“Because I believe your story, Mrs. Lawrence.  And so long as there is any way to keep your name clear of the whole miserable mess, I shall do so.”

“But if you arrest my husband—­”

“I have no intention of doing that, either—­unless I am convinced that he was in the city when the shooting occurred.  I am not in favor of indiscriminate arrests.  In this case, they can do nothing but harm.”

“You are very good,” she said softly.  “I didn’t imagine that a detective—­”

“Some of us are human beings, Mrs. Lawrence.  Is that so strange?”

She did not answer, and for several minutes they sat in silence—­each intent in thought.  It was Carroll who broke the stillness: 

“Do you know William Barker?”

“Barker?  Why, yes—­certainly.  He was Mr. Warren’s valet.”

“I know it.  Have you seen Barker since the night Mr. Warren was killed?”

“Yes.”  He could scarcely distinguish her answer.  “Twice.”

“He called here?”

“Yes.”

“Was your husband at home on either occasion?”

“No.”

“Why did he come here?”

She hesitated, but only for the fraction of a second.  “It was Barker who was driving me to distraction.  He knew that I was the woman in the taxicab.  He really believes that I killed Mr. Warren.  He has been blackmailing me.”

“A-ah!  So that explains his visits, and his plentiful supply of money?”

“Yes.  Oh! it was shameful—­that I should be so helpless before his demands.  It didn’t matter that I had nothing to do with the killing—­it was enough that I had to pay any price to keep my name clear of scandal.  Looking back on the affair now, Mr. Carroll—­I cannot understand my own weakness.  But I felt that I owed it to my husband and my sister to protect them from scandal at any cost—­and I have paid Barker a good deal of money—­”