Chapter 5 BATS IN THE WALL.

Left to himself within the banking-room, Detective Hook, with the closest scrutiny, began a systematic examination of the rifled vault and its surroundings.

There was no evidence that the bank had been entered other than by the rear doors from the Rector street side.

And these doors, strange to relate, were unprotected, save by ordinary spring locks.

Evidently the officers of the Webster Bank had relied upon the solidity of their vault doors for protection, and upon the fact that with plate glass windows upon two sides, facing Rector street and Broadway, the policeman on the beat could see the entire front of the vault as plainly as though it had been standing in the street itself, by the light of the gas-burner, kept burning the entire night directly in front of the combination lock.

And, after all, no better protection could be devised than this, providing always, the policeman of the beat is true to his trust.

And yet the deed had been done, and, stranger still the officer in whose charge this portion of Broadway lay had put in no appearance yet.

Crowbar and jimmy, powder-can and fuse, and the shattered door itself, told with startling plainness the methods by which the bank-robbers had attained their end.

Detective Hook examined each point with close attention.

Nothing of value remained in the vault.

It might have contained millions-it might have contained cents-the bank officers alone could tell.

"There is something altogether out of the usual order in this affair," he muttered to himself, as he stood musing before the rifled vault.

"The strange hints received by me from Cutts have proved both true and false. Instead of this clerk and a gang of desperate burglars, I find the vault already robbed and this young man with his strange story, involving Cutts himself, standing here alone.

"I don't like the look of it. I believe this boy is as innocent as I am, Caleb Hook; there is something else at the bottom of all this. If I don't greatly mistake--

"Hello! Well, what have you discovered?"

"Nothing," replied Policeman Jones, now appearing at the door. "There's not a soul anywhere about, except an old crazy woman walking up and down before Trinity Church, muttering to herself. I questioned her closely, but she knows nothing at all."

"Did you see anything of Officer Flaherty, who ought to be on this beat?"

"Not a thing, and I've searched for him everywhere, too."

"I'll see that he is provided for, the careless rascal," muttered the detective, "and you, Brady"-addressing the second policeman who had also appeared-"what luck in the church-yard? Any tracks in the snow?"

"The tracks of two men, Mr. Hook, but they are pointing this way. Just over the fence are others, too. I should say several persons had been tramping around there."

"Remain here and guard what is left," said the detective, briefly. "I'll examine into this for myself."

He hastily passed to the street, leaving the two policemen in charge.

"Now for the Trinity church-yard," he muttered, as he sprang toward the low wall at the point before which the strange woman had kneeled but a few moments before. "I've got a genuine mystery on my hands at last, I fancy, and that's what I've been sighing for these last three months-- Ha, Schneider, where's your prisoner? Surely you are not back from the station as soon as this?"

The stout German policeman, panting for a breath, stood trembling by his side.

"Dunder und blitzen! now mebbe you kills me, Mr. Hook. I swear it vos not my fault."

"Not your fault! Have you lost your prisoner-but that is impossible! Speak, you Dutch scoundrel! Where is the boy I gave into your charge?"

"Gone, Mr. Hook! Disappeared unter mein very nose. I take not mein eyes from him, und I looks for him und he ish not dere. I tink dere's some devil vork mit dis, by shiminy, I do!"

A moment later, and Detective Hook, with the frightened German by his side, stood beneath the high wall skirting Trinity church-yard on the New Church street side, at the spot where Frank Mansfield had so strangely disappeared.

Twice over had the wretched Schneider told his tale, without rendering matters in the least more clear.

If he told the truth-and he related the facts so circumstantially that there could be no doubt of that-there was absolutely no explanation to be had.

There was the dead wall upon one side broken only by the iron doors, leading to the vaults beneath the bank, which had not been opened, perhaps in a century, filled with the moldering bones of the long-forgotten dead, and the structure of the elevated railroad upon the other, with the dark outlines of the building upon the opposite side of the street rising just beyond.

That the boy could have crossed the street was a simple impossibility.

Not a trace of human foot was visible in the freshly fallen snow.

Upon the sidewalk beneath the wall the detective had no difficulty in tracing his footsteps.

But this only served to double the mystery.

They all pointed one way-in the direction of the station toward which they had been going, and at the precise point where the boy had halted when the attention of his conductor had been attracted by the bat-like cry from the wall above they ceased to appear at all.

It was impossible that the vanished prisoner could have advanced or retreated, crossed the street-moved up or down.

Deeply puzzled, the detective hurried to Rector street again, and leaped the iron fence at the first available point, landing among the stones of the grave-yard beyond.

Nor did he leave it until an hour had passed, and but little the wiser then.

The tracks of two men crossing toward the Rector street side of the grave-yard from a point overlooking the place where Frank had disappeared were found and carefully measured.

At this point, also, the snow was found to be much disturbed, both on the ground itself and upon the vines overhanging the wall.

To all appearance, a number of persons had been moving about here, but their foot-prints seemed to lead nowhere, extending simply up and down the wall.

What did it mean?

Detective Hook had been called upon to solve many mysteries in his time, but never before had he encountered one so deep as this.

He was baffled; he could not deny it.

Accompanied by the crestfallen Schneider, he repaired to the station at last, and reported the occurrences of the night.

In a short space of time every newspaper in the city was preparing for their morning issues an account of the bold robbery of the Webster National Bank.

The great clock in Trinity steeple had rang out the hour of four, when Detective Hook, still hovering about the scene of his late defeat, turned, for the twentieth time that night, the corner of Rector street and Broadway.

As he did so there brushed past him the figure of a woman, plainly but neatly dressed, with gray hair hanging down from beneath her worsted hood, and wild, roving eyes, moving restlessly from one object to another as she walked along.

"Bats in the wall! Bats in the wall!" she muttered, as she passed. "Blessed be the bats in the wall for what they have done for my erring boy this night!"

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