They had raced madly, but now as they came up short, panting, they saw no one.  The man had disappeared.

Suddenly they heard steps on the cross street.

“Turned the corner,” panted Johnny.  “C’mon!”

Again they dashed ahead, slowing only as they reached the other street.

Sure enough, halfway down the block they saw their man.  He was walking rapidly toward the bridge.  Quickening their pace they followed.

Distinctly they saw the man go upon the bridge.  Very plainly they heard every footstep on the echoing planks.  Then, just as they were about to step upon the bridge, the footsteps ceased.

“Sh!” whispered Johnny, bringing his friend to a halt.  “He’s stopped; maybe laying for us.”

For a minute they stood there.  The lapping of the water was the only sound till, somewhere in the distance an elevated train rattled its way north.

“C’mon,” said Johnny.  “We’ve met that bird in worse places than this; we can meet him again.”

But they did not meet him, although they walked the full length of the bridge.  There was not a place on the whole structure where a man could hide, but they searched it thoroughly.  Then Johnny searched the sides, the abutments.  He sent the gleam of his powerful flashlight into the dark depths beneath, but all to no purpose.  The man was gone.

“Humph!” said Johnny.

“Hisch!” breathed Hanada.

“Well, all I have to say,” observed Johnny presently, “is that if the old Chicago River has that fellow, he’ll be cast ashore.  The good old Chicago doesn’t associate with any such.”

They stood there leaning on the wooden railing debating their next move, when a shot rang out.  Instantly they dropped to the floor of the bridge.  A bullet whizzed over their heads, then another and another.  After that silence.

“Get you?” whispered Johnny.

“No.  You?”

“Nope.”

Then a long finger of light came feeling its way along the murky waters to rest on the bridge.

With a sigh of relief, Johnny saw that it came from a police-boat down stream.  The light felt its way back and forth, back and forth across the river, then up to the bridge and across that.  It came to rest as it glared into their eyes.  It blinked one, two, three times, then went out.

“I’m glad they didn’t hold it on us,” breathed Johnny.  “In that light anybody that wanted to could get a bead on us.”

Hearing heavy, hurrying footsteps approaching, they stood up well back against the iron braces.

“Police!” whispered Johnny.

“You fellows shoot?” demanded one of the policemen as they came up and halted before the two boys.

“Nope,” Johnny answered.

“No stallin’ now.”

“Search us,” Johnny suggested.  “The shots were fired at us, though where from, blessed if I know.  Came right out of space.  We’d just searched the bridge from end to end.  Not a soul on it.”