“What’d y’ search it fer?”

“A man.”

“W’at man?”

“That’s it,” Johnny evaded.  “We wanted to know who he was.”

The policemen conversed with one another in low tones for a moment.

“One of the bullets struck a cross-arm; I heard it,” suggested Johnny.  “You can look at that if it’ll be any comfort to you.”

The policeman grunted, then following Johnny’s flashlight, examined the spot where the bullet had flaked the paint from the bridge iron.

“Hurum!” he grumbled.  “That’s queer.  Bullet slid straight up the iron when it struck.  Ordinarily that’d mean she was shot square against it from below and straight ahead, but that can’t be, fer that brings her comin’ direct out of the river, which ain’t human, nor possible.  There wasn’t a boat nor a barge nor even a plank on the river when the searchlight flashed from the gray prowler; was there, Mike?”

“Not even a cork,” said Mike.

“Well, anyway, that clears youse guys,” grunted the leader.  “Now you better beat it.”

Bidding Hanada good night, Johnny walked across the bridge, around four blocks, then made a dash for his room.  There was dust on his blankets, but he could shake it off.  Anyway, he probably would not sleep much that night.  Probably he would spend most of the night sitting by the window, listening to the lap of the waters of the old river and trying to solve the strange problem of the bullets fired apparently from the depths of the stream.

CHAPTER XV

THE CAT CRY OF THE UNDERWORLD

Dodging in front of a street car, Johnny turned abruptly to the right and trailed a taxi for half a block; then he shot across the sidewalk to the end of a dark alley.  Then he flattened himself against the wall and listened.  Yes, it came at last, the faint thud of cautious footsteps.  He had not thrown the man off the scent.

“Well then, I will,” he muttered, gritting his teeth.  Johnny was a trifle out of sorts to-night.  The chase annoyed him.

He dodged down the alley, then up a narrow court.  Prying open the window of an empty building, he crept in and silently slid the sash back in its place.  Tiptoeing across the hall with the lightness of a cat, he crept up the dusty stairs.  One, two, three flights he ascended, then feeling for the rounds of a short ladder, he climbed still higher, to lift a trapdoor at last and creep out upon the roof.

Once there he skulked from chimney to chimney until he had crossed the flat roofs of three buildings.  The third had a trapdoor close to a chimney.  This he lifted, then dropped behind him.  He was now in his own building.  Panting a little from the exertion, he tiptoed down the hall, turned the key and entered his room.

Having made sure that the iron blinds were closed, he snapped on a light.  His eyes, roving around the room, fell presently upon something white on the floor.  Johnny could see his own name scrawled upon it.  There were but a few people in all the world who knew that Johnny Thompson had ever lived here.  Probably all of those who did know thought him dead and buried in Russia.  Who had written this note?  Friend or foe?