From garret to cellar, thirty rooms in all; nothing but the hand-print on the newel-post and the opened trunk.  Haggerty returned to the museum, turned out all the lights except that on the desk, and sat down on a rug so as not to disturb the dust on the chairs.  The man might return.  It was certain that he, Haggerty, would come back on the morrow.  He was anxious to compare the thumb-print with the one he had in his collection.

For what had the man come?  Keep-sakes?  Haggerty dearly wanted to believe that the intruder was the one man he desired in his net; but he refused to? listen to the insidious whisperings; he must have proof, positive, absolute, incontestable.  If it was Crawford’s man Mason, it was almost too good to be true; and he did not care to court ultimate disappointment.

Proof, proof; but where?  Why had the man not returned the clothes to the trunk and shut it?  What had alarmed him?  Everything else indicated the utmost caution. . . .  A glint of light flashing and winking from steel.  Haggerty rose and went over to the window.  He picked up a bunch of keys, thirty or forty in all, on a ring, weighing a good pound.  The detective touched the throbbing bump and sensed a moisture; blood.  So this was the weapon?  He weighed the keys on his palm.  A long time since he had seen a finer collection of skeleton keys, thin and flat and thick and short, smooth and notched, each a gem of its kind.  Three or four ordinary keys were sandwiched in between, and Haggerty inspected these curiously.

“H’m.  Mebbe it’s a hunch.  Anyhow, I’ll try it.  Can’t lose anything trying.”

He turned out the desk light and went down to the lower hall, his pocket-lamp serving as guide.  He unlatched the heavy door-chains, opened the doors and closed them behind him.  He inserted one of the ordinary keys.  It refused to work.  He tried another.  The door swung open, easily.

“Now, then, come down out o’ that!” growled a voice at the foot of the steps.  “Thought y’d be comin’ out by-’n-by.  No foolin’ now, ’r I blow a hole through ye!”

Haggerty wheeled quickly. “’S that you, Dorgan?  Come up.”

“Haggerty?” said the astonished patrolman.  “An’ Mitchell an’ I’ve been watchin’ these lights fer an hour!”

“Some one’s been here, though; so y’ weren’t wasting your time.  I climbed up th’ fire-escape in th’ alley an’ got a nice biff on th’ coco for me pains.  See any one running before y’ saw th’ lights?”

“Why, yes!”

“Ha!  It’s hard work t’ get it int’ your heads that when y’ see a man running at this time o’ night, in a quiet side-street it’s up t’ you t’ ask him questions.”

“Thought he was chasin’ a cab.”

“Well, listen here.  Till th’ owner comes back, keep your eyes peeled on this place.  An’ any one y’ see prowling around, nab him an’ send for me.  On your way!”

Haggerty departed in a hurry.  He had already made up his mind as to what he was going to do.  He hunted up a taxicab and told the chauffeur where to go, advising him to “hit it up.”  His destination was the studio-apartment of J. Mortimer Forbes, the artist.  It was late, but this fact did not trouble Haggerty.  Forbes never went to bed until there was positively nothing else to do.