“I made inquiries in that direction, Monsieur,” was the reply.  “I have the words of the servants at the door and of the stenographer that there were no callers, and the statement of the stenographer that there were no telephone calls or telegrams.  There were only four letters for him personally.  He left them all on his desk—­here they are.”

Mr. Grimm looked them over leisurely.  They were commonplace enough, containing nothing that might be construed into a reason for the disappearance.

“The letters Monsieur Boissegur had dictated were laid on his desk by the stenographer,” Monsieur Rigolot rushed on volubly, excitedly.  “In the anxiety and uneasiness following the disappearance they were allowed to remain there overnight.  On Wednesday morning, Monsieur”—­and he hesitated impressively—­“those letters bore his signature in his own handwriting!”

Mr. Grimm turned his listless eyes full upon Monsieur Rigolot’s perturbed face for one scant instant.

“No doubt of it being his signature?” he queried.

“Non, Monsieur, non!” the secretary exclaimed emphatically. “Vous avez—­that is, I have known his signature for years.  There is no doubt.  The letters were not of a private nature.  If you would care to look at copies of them?”

He offered the duplicates tentatively.  Mr. Grimm read them over slowly, the while Monsieur Rigolot sat nervously staring at him.  They, too, seemed meaningless as bearing on the matter in hand.  Finally, Mr. Grimm nodded, and Monsieur Rigolot resumed: 

“And Wednesday night, Monsieur, another strange thing happened.  Monsieur Boissegur smokes many cigarettes, of a kind made especially for him in France, and shipped to him here.  He keeps them in a case on his dressing-table.  On Thursday morning his valet reported to me that this case of cigarettes had disappeared!”

“Of course,” observed Mr. Grimm, “Monsieur Boissegur has a latch-key to the embassy?”

“Of course.”

“Anything unusual happen last night—­that is, Thursday night?”

“Nothing, Monsieur—­that is, nothing we can find.”

Mr. Grimm was silent for a time and fell to twisting the seal ring on his finger.  Mr. Campbell turned around and moved a paper weight one inch to the left, where it belonged, while Monsieur Rigolot, disappointed at their amazing apathy, squirmed uneasily in his chair.

“It would appear, then,” Mr. Grimm remarked musingly, “that after his mysterious disappearance the ambassador has either twice returned to his house at night, or else sent some one there, first to bring the letters to him for signature, and later to get his cigarettes?”

“Certainement, Monsieur—­I mean, that seems to be true.  But where is he?  Why should he not come back?  What does it mean?  Madame Boissegur is frantic, prostrated!  She wanted me to go to the police, but I did not think it wise that it should become public, so I came here.”