"You're boss, then," said Burke.

"I have not come to this country for nothing," said Doctor Zerndorff. "I have been here a long time. Five years, yes?

"Since I have come here - to help your government, I have done much. I have helped you, too, inspector.

I have seen these men in Europe - the same men that have come to this country now - to do crime. I can find them because I know them.

"I have seen them work in Berlin. I have been to Italy, Spain -"

He shrugged his shoulders and spread his hands in a characteristic gesture.

"You figure there's communists in back of it?" observed the inspector. "It certainly looks that way. You ought to know. Coming right after May Day, when we broke up those celebrations they tried to hold, it looks like a straight Bolshevik move."

"A campaign of terrorism, that's what it is! We want to stop it! Soon!"

"They picked the spots, all right," said Cardona.

"Ah, yes," agreed Doctor Zerndorff. He began to count on his fingers. "The first, you see, was in Wall Street, the place that means money - capital.

"Then in the big station was another bomb and in the subway. That has frightened the people. But the most important has been the newspaper office.

"It is the newspaper which has done much to hurt these bomb men!"

"How do you figure they framed it?" questioned Cardona.

"Framed? Ah, yes! You mean, how they have planned? I cannot say. My brain" - Doctor Zerndorff tapped his forehead - "is not yet to tell you how they have done this. It is to tell you who has done these things.

"You, Mr. Detective, can find out how these things were done. That will be your evidence, yes? I shall help you, but right now I am seeking to find those men we want!"

"The nearest we can figure," said Cardona, "is that the Wall Street bomb was planted in an ash can beside a building. But no one saw it done.

"We think the Grand Central bomb was put in the showcase of the cigar stand. There we've got something to work on. It must have been delivered in a package.

"The subway bomb, up at Columbus Circle, could have been planted by almost anybody; we figure it was under one of the long wooden seats, inside the turnstiles.

"But we can't dope out how one was shoved into the managing editor's office at the Evening Cla.s.sic." "Very soon," said Zerndorff quietly, "I shall tell you who the men may be. You must find out those men that you suspect.

"Then we shall fit like this" - he joined his spread fingers - "and we shall know enough to make those arrests that Mr. Inspector wishes."

"We've been looking for planted bombs," said Burke. "We haven't found any. Maybe that means there's going to be no more explosions."

"We think there were four killed in the Cla.s.sic office, and there were a lot badly injured," said Cardona.

"We've identified the managing editor and two reporters; but we think there was another there - a Russian."

Zerndorff raised his brow.

"A cab driver brought him to the Cla.s.sic office along with one of the reporters, Tewkson. The other reporter, Grimes, met them.

"It may be that the Russian was going there to warn Raynor, the managing editor. There was a five-thousand-dollar reward, you know."

"It is strange," said Doctor Zerndorff. "It is very strange, yes. These men that say they are communists, that want no money. They are the first to try to get money when it is offered to them!"

"Maybe we can bait some of them!" said Burke bluntly.

The white-haired criminologist shrugged his shoulders. He seemed speculative for a few moments; then he spoke slowly and thoughtfully, making much of his words.

"We have to deal with a carefully deliberated crime," he stated. "Not the kind that springs from anger or from the quick impulse. It is the crime of the plotter, of the man that moves by stealth.

"Who is the man? Maybe I could tell you now. But I must have more time to think; I must not make a big mistake. It may not be just the one man - it may be two or three. But these will be the men who plan.

"Beneath them are the little men, those who have placed the bombs where they have exploded. You must find them, Herr Inspector. Have them for me!"

"You're right, professor," interposed Burke. "Joe Cardona will get the small fry. Leave it to him. But how long will it be before you haul in the big shots?"

"It shall not be long. I shall tell you this. It is not the time of which I am thinking. It is of explosions."

"Just what do you mean by that?"

"There have been one - two - three - four," replied Doctor Zerndorff, counting on the fingers of his left hand. "Perhaps there shall be no more. Perhaps" - he pointed to the last outstretched finger - "perhaps there shall be one more, yes?

"If that is so, I can promise you, there will be no more after that."

"We don't want any more if we can help it!"

"Listen to me, Herr Inspector." Zerndorff's voice was emphatic. "My brain" - he tapped the fingertips of both hands against his forehead - "my brain is understanding. I am like one who is in dreaming, yes? "People I can see. Faces I can recognize; but I cannot grasp. Should they move once, I shall have them.

But I can only wait.

"Perhaps they shall not move. If they do not, my brain shall work of itself and I shall find them. You understand me, yes?"

"It's plain enough to me, chief," said Cardona, tuning to Inspector Burke. "The professor here knows what he is doing. I've been in the same fix myself. He's waiting to play his trump card. That's all."

"I get you!" said the inspector. "All right, professor, we're counting on you!"

Doctor Zerndorff rose and the other men followed. The three went downstairs together in the elevator.

On the ground floor, the professor placed his finger against his lips, and then spoke softly in the mellow light of the empty hallway.

"Up to now," he said, "these men have struck for just one thing - to frighten. Perhaps they shall try to scare again. I think so, yes.

"Perhaps you, Herr Detective, can discover them before they strike! A bomb - you may find somewhere.

But after that, they shall not try to scare. They will only protect themselves.

"They may fight, yes? If they do, who is the one they shall fight? The police? I say no! The police are too many.

"Here is the one" - he tapped his chest expressively. "I am the one, yes; the one that they shall fight! They know that I know. You understand? There is danger, or there will be danger, here in New York, for me!"

"That sounds logical, chief," observed Cardona, looking at Inspector Burke.

"So," said Doctor Zerndorff quietly, "do you think that I shall wait? No, no! It is for my own safety that I should see these men in prison.

"You may think of the public, Herr Inspector. That is good. I think, too, of the public - but," he smiled, "I think also of myself!"

He went to the outer door and carefully unbarred it. Standing in semidarkness, he peered across the street. An automobile lurked beside the opposite curb.

"See?" whispered Doctor Zerndorff. "It may be now. I am suspicious. Friend or foe, I know not. So go, my friends, and remember that I shall solve this plot for you!"

Burke and Cardona stepped to the street. The door closed behind them. They heard the click of bolts.

The inspector coughed uneasily.

"Let's get the lay, Joe," he said.

The two men walked boldly across the street. They saw two shadowy forms seated in the front seat of the sedan. Cardona's fingers sought the b.u.t.t of his automatic.

"What're you doing here, buddies?" he asked.

Something sparkled on the breast of the man beside the wheel. In the reflected light of the street, Cardona recognized the badge of a secret-service agent. "h.e.l.lo, Cardona," came a low voice. "That's Inspector Burke with you, eh?"

"Right-o!" replied the detective.

"We watched you go in," came the voice. "We've been waiting for you to come out. We're detailed here to protect Doctor Zerndorff."

Cardona was positive of the ident.i.ty of the men. He looked at Burke and the inspector nodded his approval.

"We may have a police detail up here, later on," said the detective.

"Okay," came the voice from the car. "Tell them we're here. We'll know them."

Cardona hailed a pa.s.sing taxi. He waved to the men in the sedan as he and Inspector Burke entered the cab. Then the street became silent. The secret-service men's automobile remained across the street.

The lights in the upstairs apartment went out, but the government men continued their vigil. In their keeping was the safety of the man in whose hands might lie the key to a nationwide plot of which the Manhattan explosions might be but forerunners.

A car going rapidly pa.s.sed close by the parked automobile. The sharp eyes of the secret-service men were busy as they peered into the darkness of the pa.s.sing coupe. It contained only the driver. One of the secret-service men sat up suddenly and nudged his companion.

"Did you hear that?" he exclaimed.

"No," said the other, "what was it?"

"It sounded like a low laugh - like a whispered laugh!"

The eyes of the watchers followed the taillight of the coupe until it disappeared in the distance. Then both men settled back to resume their vigil.

One - the man at the wheel - was calm and indifferent. The other was thoughtful and his mind was troubled.

For through his brain pa.s.sed the haunting recollection of a sinister sound - a laugh so unreal that he could scarcely believe that his ears had not deceived him.

He felt confident that the coupe had come down that street for some special purpose; yet he could not imagine what its mission might have been.

The secret-service man was not acquainted with the underworld of New York. Had he known more, he might have understood. He would have attributed that laugh to more than fancy.

For that tone of sinister merriment had struck terror into the hearts of many gangsters. It was the laugh of The Shadow!

CHAPTER IV. THE HANDS OF THE SHADOW.

INSPECTOR BURKE and Detective Cardona were sitting in the office at police headquarters. Outside, through the misty night, a clock boomed out the hour of eleven. The two men had just returned from their interview with Doctor Zerndorff. Inspector Burke laid a sheet of paper on the desk in front of him. He began to write rapidly in pencil.

Cardona, watching him, knew what he was doing.

Burke possessed a photographic mind. Whenever the inspector held an important interview, he later wrote down the facts from memory. His task completed, Burke handed the sheet of notations to Cardona. The detective read it and nodded in admiration.

"You've got everything there, chief," he said.

Burke smiled and folded the piece of paper. He pocketed it. The next day it would be typed and filed - a record of everything that Doctor Zerndorff had said. This would remain as secret police data.

There was a knock at the door.

"Come in," called Cardona.

A tall, stoop-shouldered man entered. He was clad in overalls. His face was a dull white. He carried a bucket and mop.

Cardona grinned. This was Fritz, the janitor, the faithful servitor of police headquarters.

"Want to clean up, Fritz?" asked the detective.

"Yah," was the reply.

"Well, we're going. You're on the job late again, aren't you?"

"Yah."

Inspector Burke looked at the janitor. He smiled and shook his head.

"I never saw the like of you, Fritz," he observed. "Just because we work late, you work late. I wish some of the force would profit by your example.

"Come on, Joe. We'll let Fritz finish up."

As the men left the room, Fritz was at work. He was dull, slow, and methodical. He continued his task while the footfalls of the departing men echoed from the corridor. Finally he reached the desk where Inspector Burke had been seated.

Here Fritz laid aside his mop, resting it against the wall. From his overalls he drew forth a sheet of thin paper. He studied the surface of the desk and laid the paper upon it. He pressed the sheet flat and rubbed it with his fingers.