At ten minutes past nine, exactly, the door opened, and a thick-set, florid man, buttoned up in a fawn colored raincoat and wearing a bowler hat of obsolete build, entered.  He possessed a black mustache, a breezy, bustling manner, and humorous blue eyes; furthermore, when he took off his hat, he revealed the possession of a head of very bristly, upstanding, black hair.  This was Detective-Sergeant Sowerby, and the same who was engaged in examining a newspaper in the study of Henry Leroux when Dr. Cumberly and his daughter had paid their second visit to that scene of an unhappy soul’s dismissal.

“Well?” said Dunbar, glancing up at his subordinate, inquiringly.

“I have done all the cab depots,” reported Sergeant Sowerby, “and a good many of the private owners; but so far the man seen by Mr. Exel has not turned up.”

“The word will be passed round now, though,” said Dunbar, “and we shall probably have him here during the day.”

“I hope so,” said the other good-humoredly, seating himself upon one of the two chairs ranged beside the wall.  “If he doesn’t show up."...

“Well?” jerked Dunbar—­“if he doesn’t?”

“It will look very black against Leroux.”

Dunbar drummed upon the blotting-pad with the fingers of his left hand.

“It beats anything of the kind that has ever come my way,” he confessed.  “You get pretty cautious at weighing people up, in this business; but I certainly don’t think—­mind you, I go no further—­but I certainly don’t think Mr. Henry Leroux would willingly kill a fly; yet there is circumstantial evidence enough to hang him.”

Sergeant Sowerby nodded, gazing speculatively at the floor.

“I wonder,” he said, slowly, “why the girl—­Miss Cumberly—­hesitated about telling us the woman’s name?”

“I am not wondering about that at all,” replied Dunbar, bluntly.  “She must meet thousands in the same way.  The wonder to me is that she remembered at all.  I am open to bet half-a-crown that you couldn’t remember the name of every woman you happened to have pointed out to you at an Arts Ball?”

“Maybe not,” agreed Sowerby; “she’s a smart girl, I’ll allow.  I see you have last night’s papers there?”

“I have,” replied Dunbar; “and I’m wondering"...

“If there’s any connection?”

“Well,” continued the inspector, “it looks on the face of it as though the news of her husband’s death had something to do with Mrs. Vernon’s presence at Leroux’s flat.  It’s not a natural thing for a woman, on the evening of her husband’s death, to rush straight away to another man’s place"...

“It’s strange we couldn’t find her clothes"...

“It’s not strange at all!  You’re simply obsessed with the idea that this was a love intrigue!  Think, man! the most abandoned woman wouldn’t run to keep an appointment with a lover at a time like that!  And remember she had the news in her pocket!  She came to that flat dressed—­or undressed—­just as we found her; I’m sure of it.  And a point like that sometimes means the difference between hanging and acquittal.”