"You know best, professor," said Inspector Burke. "You're expecting the government men; you've talked with them already, and this is their job as well as ours."
"But don't forget what we're up against. We have to police this city. Four explosions in one day is bad stuff! We don't know what to expect next!"
"You are watching?" the professor queried.
"We are! If they try anything in any public place, we may spot it before it breaks."
"But we don't want any more bombings! If any more are scheduled, we want to find it out!"
"I've been after evidence, professor," interrupted Cardona, "and I'll say it's tough to get. When one of those bombs goes off, it wrecks everything!
"There'll be some clues that'll show up, right enough, but how soon will we get them?"
"We're counting on you to spot the men for us, professor," interposed Burke. "You say you will be able to find them. Why not do it right now, so they won't give us any more trouble?"
"Right now, yes?" questioned Zerndorff, with a faint smile. "You want them right now, yes? Do you want them all at once, or some of them now and more of them at some time later?"
"We want all we can get, whenever we can get them!"
"Inspector," said Zerndorff, spreading his hands in a slight, unconscious gesture, "you must understand, as I do, the men with whom we have to deal.
"As our friend here, the detective, has said, we must have evidence. We must take them all when we do take them. Not just one or two, but all! I shall tell you why, yes?
"It is because if we take part of them, the others will continue to do what they have done. They will try to make it seem that those whom we have taken first had nothing to do with these explosions that have gone before! You understand, yes?"
"The professor is right, inspector," said Cardona, nodding. "I get his point. He figures that they are going to lay low for a while, anyway.
"If we wait them out we can make a real clean-up. But if we move too fast, they'll blow the works. We want to round up the whole crew!"
"That may be right," said Burke, nodding. "What about the secret-service men, professor?"
"They agree with me, inspector."
"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 Classic."
"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 Classic 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 Classic 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."