“Perfectly,” said Leverage.  “Go ahead.”

“Walters gets the signal and drives up.  Mrs. Lawrence gets in.  He drives away.  And then—­”

Leverage leaped forward eagerly:  “Yes—?? and then?”

“Well,” said Carroll slowly, “we don’t know what happened in that taxicab.  We believe that Mrs. Lawrence is a decent woman.  We know that Warren would have gone through with the elopement.  That being the case, we can fancy his keen disappointment.  Under those circumstances, Eric—­a good many things could have occurred in that taxicab which might have justified Warren’s death at her hands.”

Leverage crossed to his desk, from the top drawer of which he took a box of cigars.  He was frowning as he recrossed to Carroll and offered him one.  Then, with almost exasperating deliberation, the head of the police force clipped the end of his own cigar, held a match to it, replaced the box in his desk and took up his post before the fire—­with his back to it so that he could watch Carroll’s face.

“You really want to believe that story, don’t you, David?” he asked gently.

“Yes.”

“And yet you know it is shot all full of holes.”

“How?”

“For one thing,” said Leverage slowly—­“how do you explain the fact that it was a.32 that killed him.  Not that a .32 is any big gun—­it isn’t—­but it does make a considerable racket.”

“The shooting probably took place at the R.L.&T. crossing while the train was passing.  The sound of the shot may have been drowned in the roar of the train—­not entirely smothered of course, but sufficiently blended with the other noise not to attract the attention of the half-frozen driver.  And, the cab being stopped there, it must have been at that point that Mrs. Lawrence—­panicky over what had occurred—­left the taxi.”

“You’re a dandy little ol’ explainer, Carroll.  But you’ve forgotten one other important item.”

“What is it?”

“The address Mrs. Lawrence gave—­981 East End avenue.  That address was a stall—­we know it was a stall.  We were hot on that end of it the night the body was found.  And if those two people were trying to get home, Carroll—­if Warren was already in the cab and Mrs. Lawrence gave the address—­and if she wanted to get away from Warren and safe at home as soon as she could—­she’d never have ordered Walters to drive to 981 East End avenue!”

Carroll did not answer.  There was no answer possible.  Leverage’s logic was irrefutable.  And finally Carroll rose to his feet and slipped into his heavy overcoat.  Leverage’s eyes were turned kindly upon him.

“Where are you going, David!”

“I’m going to play my last trump.  If it doesn’t uncover something—­I throw up my hands.  Laugh at me if you will, Eric—­rail at me for being chicken-hearted, for playing hunches too strongly—­but I have an idea that Mrs. Lawrence did not kill Warren.  Don’t ask me how or why?  I don’t know—­I admit that frankly.  But I’ve always banked on my knowledge of human nature, Leverage—­and my instinct has never yet betrayed me.  Just now it is forcing me to give this woman every chance in the world to clear herself.  I am hoping that circumstances will allow me to bring this case to a conclusion without making public her connection with it—­the elopement she was planning.”