It was nearly sunset one Monday afternoon, and almost two weeks subsequent to the incidents last depicted.

That at least one of Dave Kilgore's suggestions had been adopted, and he and his gang had become rigorously guarded, appears in that the Carters had utterly failed to accomplish anything against them in the interval mentioned. Despite constant vigilance and incessant work on the case, neither Nick nor Chick had been able to secure an additional clew.

Kilgore and Matt Stall had vanished as if the earth had swallowed them.

The mammoth vaudeville troupe had completed its engagement, and was now disbanded for the season.

Senora Cervera still retained her uptown house, and frequently received Venner as a visitor; but never a sign of the diamond gang, or of any stranger, could the detectives discover, in or about her place.

Rufus Venner was attending to his business as usual, and appeared all aboveboard. Now and then he called upon Nick about the stolen diamonds, expressing a hope that they would be recovered; but in no way did he lay himself open to further suspicions than Nick had at first conceived.

Yet Nick was too shrewd to press him with questions, and so perhaps betray his own hand. As a matter of fact, the famous detective was in quite a quandary over the case, because of his conviction that some big game was secretly afoot, and his utter inability to strike any tangible clew to it.

Such a state of affairs was very unusual, and Nick chafed under it. It indicated that he was up against men as good as himself, and his vain work of the past ten days served only to aggravate him, and embitter his grim and inflexible determination to unearth the whole business.

This Monday afternoon, as Nick and Chick were pa.s.sing Central Park, the attention of the latter was drawn toward a group of men in one of the park walks, somewhat removed from the street. A policeman was among them, and they appeared to be gazing at something upon the ground.

"It looks like the figure of a woman," said Nick, as he and Chick entered the park. "Officer Fogarty is there, and--yes, by Jove! it is the form of a woman."

The two detectives quickly reached the scene, and the park officer at once recognized Nick, respectfully touching his helmet.

"What's amiss here, Fogarty?" inquired Nick.

Fogarty pointed to the motionless form upon the ground.

"Dead!" said he, tersely. "We've just found her."

"Keep those people further away, Fogarty," said Nick, with a toss of his head toward half a score of men gathered near by. "I will see what I make of the case."

The figure was that of a girl, rather than a woman, apparently about eighteen years of age. She was lying partly upon her side upon the greensward, and evidently had fallen from one of the park seats upon which she had been resting, and upon which her straw shade hat was still lying. She was neatly clad in a suit of dark blue, and her girlish face indicated some culture and refinement.

Near her, upon the gra.s.s, lay a piece of brown wrapping paper, and a yard of two of string, evidently removed from a small, square box, which she had dropped and partly fallen upon when stricken with sudden death.

A mere glance gave Nick these superficial features, and he quickly knelt beside the girl, and felt her hand and wrist.

"Dead as a doornail," he murmured to Chick, who also had approached. "I find her hand still warm, however. She can have been dead only a few minutes."

"Heart failure, perhaps," suggested Chick.

"I don't think so."

"Why?"

"She doesn't look it. Her form is plump, her cheeks full, and she appears to have been in perfect health."

"Yet she is dead."

"No doubt of it."

"A pretty girl, too."

"Very. See if there is any writing on that brown paper."

"No, Nick; not a line."

"Here, here, let me see it! What's this? It is punctured with tiny holes, evidently made with a pin."

"So it is, by Jove!"

"Perhaps she made them with her hat pin, while sitting there on the seat. See, Chick, there is the pin still in the hat."

"I see it, Nick. What now?"

Still kneeling beside the girl, Nick was holding the sheet of paper between himself and the sky.

"No, the punctures are not uniform," said he. "I thought that they possibly had been made with some design, and perhaps formed some word or sentence that would give us a clew to the mystery."

"None such, eh?"

"Not a sign of it. Evidently she jabbed the pin through the paper only in idleness."

"She is lying on a box of some kind, from which she probably had taken this wrapping paper."

"So I see," nodded Nick. "Lend me a hand, Chick, and we'll have a look at the box."

With gentle hands the two detectives moved the girl's lifeless form, and Nick then took up the box mentioned.

It was about four inches square, and was made of silver, with an open work design of vines and leaves, which displayed a blue silk lining through the metal apertures. Plainly enough it was a lady's jewel casket, and one of considerable value; but it was entirely empty, and it bore no name or inscription.

For several moments Nick Carter examined it very intently, with his brows gradually knitting closer and closer; and all the while Officer Fogarty, and the group of men in the gravel walk a few yards distant, mutely gazed and wondered.

Chick Carter, however, who could read Nick's every change of expression, saw at once that the great detective not only was making some startling discoveries, but also was arriving at deductions far too subtle and significant to have been reached by any less keen and practiced observer.

"What do you make of it, Nick?" whispered Chick, dropping to his knee beside his companion.

Nick also lowered his voice, and for several minutes the two conversed in rapid whispers.

"It is a jewel case, Chick; and quite a valuable one."

"So I see."

"I don't think it belonged to this girl. She looks as if she were the maid, or possibly the companion, of some woman of wealth or distinction.

Her attire also indicates that. Hence so valuable a toy can hardly have belonged to the girl, but more likely was the property of her mistress."

"No name on it?"

"Not even an initial. Not a mark of any kind."