“Was he out on business?”

“Yes, under my instructions,” Venner quickly explained.  “We have numerous old accounts on our books, and just before I went uptown I sent Spaulding out to try to make a few collections.  I think he has returned by this time.”

“It does not matter, since he was out under your instructions,” said Nick, closing his notebook.  “Now, Mr. Venner, who among your employees knew you thought of buying this lot of diamonds from Hafferman, or that you had called at his store to examine them?”

“Not a soul,” was the prompt reply.

“Are you sure of that?”

“Absolutely.  I had said nothing of the matter, even to my partner, there being nothing definite about it before I saw Senora Cervera this morning.  I am sure that none of my clerks had any idea of my intentions.”

Nick was not so sure of it, yet he did not say so.  He arose and took from Venner’s desk a block of plain paper, which he laid upon the table.

“Gentlemen,” said he, “I want the signature of your firm, in the handwriting of each of you.  Kindly let me have this.”

“What’s that for?” demanded Venner, abruptly.

“I wish to make a comparison with the forged order which my assistant will presently bring from Mr. Hafferman,” Nick coolly explained.  “I would suggest that you do not delay me.”

Venner made no reply, but took a pen and signed the firm’s name upon the blank paper.

“Now yours, Mr. Garside.”

“Mine also, Detective Carter?” queried Garside, with a look of surprise.

“If you please.”

“Surely,” cried Venner, with some resentment, “you do not suspect that Mr. Garside or myself—­”

“Pardon me!” Nick bluntly interrupted.  “I am not in the habit of discussing my suspicions.  That I should suspect either of you, however, is utterly absurd.”

“I should say so!”

“Therefore do not argue with me over an absurdity.  If I am to continue this investigation, gentlemen, I must do it in my own way.  Either that, or I shall drop the case at once.  Your signature, Mr. Garside.”

Garside hastened to take the pen, and dashed off the firm’s signature below that of his partner.  Nick tore the page from the block, then handed the latter to Venner.

“Now, Mr. Venner,” said he, “have each of your employees, from first to last, write his name with pen and ink upon this paper.  Don’t overlook one of them, not one, from your bookkeeper down to your office boy.  If Spaulding is still out, get his signature later, and send it to me by mail.  I will wait here while you are thus engaged.”

Venner now vaguely perceived Nick’s suspicions and design, and he could not consistently offer any remonstrance.  Yet he plainly resented the idea that any of his clerks could have been guilty of co-operation with the criminals who had committed the robbery that morning, and his dark features wore a grim and sullen expression when he took the block of paper and repaired to his main office.