Of what happened thereafter no one afterward remembered the details.  To be shut in there at the mercy of one who knew no mercy was intolerable.  It was left for Miss Cornelia to remember her own revolver, lying unnoticed on the table since the crime earlier in the evening, and to suggest its use in shattering the lock.  Just what they had expected when the door was finally opened they did not know.  But the house was quiet and in order; no new horror faced them in the hall; their candle revealed no bloody figure, their ears heard no unearthly sound.

Slowly they began to breathe normally once more.  After that they began to search the house.  Since no room was apparently immune from danger, the men made no protest when the women insisted on accompanying them.  And as time went on and chamber after chamber was discovered empty and undisturbed, gradually the courage of the party began to rise.  Lizzie, still whimpering, stuck closely to Miss Cornelia’s heels, but that spirited lady began to make small side excursions of her own.

Of the men, only Bailey, Beresford, and the Doctor could really be said to search at all.  Billy had remained below, impassive of face but rolling of eye; the Unknown, after an attempt to depart with them, had sunk back weakly into his chair again, and the detective, Anderson, was still unaccountably missing.

While no one could be said to be grieving over this, still the belief that somehow, somewhere, he had met the Bat and suffered at his hands was strong in all of them except the Doctor.  As each door was opened they expected to find him, probably foully murdered; as each door was closed again they breathed with relief.

And as time went on and the silence and peace remained unbroken, the conviction grew on them that the Bat had in this manner achieved his object and departed; had done his work, signed it after his usual fashion, and gone.

And thus were matters when Miss Cornelia, happening on the attic staircase with Lizzie at her heels, decided to look about her up there.  And went up.

CHAPTER SIXTEEN

THE HIDDEN ROOM

A few moments later Jack Bailey, seeing a thin glow of candlelight from the attic above and hearing Lizzie’s protesting voice, made his way up there.  He found them in the trunk room, a dusty, dingy apartment lined with high closets along the walls—­the floor littered with an incongruous assortment of attic objects—­two battered trunks, a clothes hamper, an old sewing machine, a broken-backed kitchen chair, two dilapidated suitcases and a shabby satchel that might once have been a woman’s dressing case—­in one corner a grimy fireplace in which, obviously, no fire had been lighted for years.

But he also found Miss Cornelia holding her candle to the floor and staring at something there.

“Candle grease!” she said sharply, staring at a line of white spots by the window.  She stooped and touched the spots with an exploratory finger.