Detective Riley emptied his automatic at the vanishing car, and growled low in his throat because he knew he had missed.

"The night clerk--" Verbeck cried. "Where was the clerk?"

They rushed back into the lobby. They heard doors slamming on the floors above as tenants, aroused by the turmoil and shooting, started an investigation. And they heard groans coming from behind the long desk.

Verbeck vaulted the counter, and cried out in surprise. On the floor, bound hand and foot, and gagged, was the night clerk of the bachelor-apartment house.

In the middle of his forehead was pasted a tiny black star!

And pinned to his breast was a card that bore this information:

To the Manager: This is just a hint that Roger Verbeck must go.

If he does not, my next demonstration will be more disastrous.

CHAPTER XVII-INTERRUPTED CONVERSATION

Detective Riley grasped the nearest telephone and sent an alarm to headquarters. Less than an hour later the report came that Verbeck's roadster had been found abandoned on a corner in the heart of the city, but that no trace of the Black Star had been discovered.

In the meantime the night clerk had told his simple story. A man had entered and asked whether a Mr. Rodney Stone lived there. The clerk said no such person was registered. Sure that no other person was in the office, the visitor pulled an automatic from his pocket and ordered the clerk to throw up his hands.

The clerk was forced to obey, and believed at the time that he was the victim of an ordinary holdup man, and rejoiced that all funds, except a few dollars, were locked in the safe, which he could not open. But his visitor walked behind the counter and forced the clerk to stretch out on the floor, threatening death if he made a sound. He bound and gagged him, pinned the card to his breast, and stamped his brow with a black star, then walked calmly to the switchboard, looked at the guest list to find the number of Verbeck's apartment, called Verbeck, held his conversation, and hurried out of the front door.

Gentlemen guests of the house in all sorts of night attire heard this story and looked upon Roger Verbeck with varied emotions. Some envied him the adventure and publicity, others feared for him, but the great majority was thinking of that warning and wondering whether they could find new quarters that day, and Roger Verbeck knew it.

The manager said nothing, for Verbeck had lived there for years and was excellent pay, but he looked worried.

"I'll discuss this matter with you later," Roger said, and he beckoned Muggs and Riley and led the way back to his apartment.

There they lighted fresh cigars and sat at the long table in the library, Muggs and Riley silent and waiting for Roger to speak.

"Well, we've got to move," he said after a time. "If we don't, the others will, for they'll be afraid the Black Star will demolish the place with a bomb. Perhaps it'll be best, after all."

"But where?" Riley asked. "He'd bomb another hotel just as quick if that's his game."

"I have a place of my own-the old Verbeck place, Riley. You know it.

Muggs knows it, too, for there we kept the Black Star prisoner for a day and night before we handed him over to the police."

"I remember it," Riley said.

"A big, old house in the middle of a block of ground, surrounded by trees and tangled underbrush. I intend to have it torn down and a new residence erected in its place after I'm married. We can go there with fuel and provisions and make ourselves comfortable. There is a telephone, so we can keep in touch with headquarters. We'll be by ourselves, and so need fear no spies of the Black Star. We can conduct our campaign from there."

"Great!" the detective exclaimed.

"No fear of spies, and n.o.body to bother us. We'll make it our headquarters. One of us can be on guard all the time. The Black Star will have to be very clever to get at us there. And if he does he'll be injuring my own property, and he'll not be hurting some outsider who has no concern in this affair. Let's get some sleep, then go ahead with our preparations."

It was noon when a much-relieved apartment-house manager saw them drive away in Verbeck's recovered roadster, the back of the car heaped high with provisions. Half an hour later they had reached the old Verbeck place and unloaded the car; Muggs had built a roaring fire in the living-room fireplace, and they were making themselves comfortable.

"This thing of working in the dark gets on my nerves," Riley admitted.

"I'd rather catch sight of this Black Star committing a crime and have a chase, a sort of running fight, and either victory or defeat at its end. But what can we do? Here we must sit, waiting for him to make a move. How do we know where he'll strike next? He may rob a bank, rifle some lady's jewel case-we can't tell. We've got to wait until he does something, and then take up the trail. You had a hot trail before, Roger-one of his men led you to him and you had a chance to get hands on him."

"I fancy that, in his egotism, he'll announce where he'll strike next," Verbeck said. "He's done it before."

"If he does it again we'll get him!" Riley said.

They made a tour of the grounds and looked through the house. There was little more than dust and cobwebs in the house, and the furniture was covered, except in the big living room and one bedroom, which they made habitable. Then they devoured the luncheon Muggs had prepared.

It was four o'clock in the afternoon when there came a knock at the front door, and when Verbeck opened it he found ten policemen and a sergeant in plain clothes standing before him.

"What's this mean?" he demanded.

"Chief's orders, Mr. Verbeck," the sergeant replied. "These men are to surround the block and guard your house."

"But that is just what we do not want!" Verbeck protested.

"Chief's orders. Here's a letter he told me to give you. He got it by messenger a couple of hours ago."

He handed Verbeck the letter. It was from the Black Star and addressed to the chief. It read:

Within four days I will commit my greatest crime since coming to your fair city.

Within four days I'll make a huge laughingstock of Roger Verbeck. His sudden change of residence will not save him from the punishment I intend administering to him.

Within four days!

Verbeck handed the letter to Riley, and faced the sergeant again.

"No doubt the chief means well, but I don't need so much police protection," he said. "There are three of us here, and all of us will not sleep at once."

"My orders, Mr. Verbeck."

"Telephone the chief," Riley suggested.

Verbeck hurried to the telephone, and called headquarters and got the chief.

"I don't want this squad of men out here, chief," he said.

"The orders come direct from the mayor, Mr. Verbeck, and he'll not countermand them. That threat of the Black Star's is too strong to be ignored. I didn't call you up before I sent the men out because I knew you'd object. Those men will not bother you. They'll surround the block and stay out of your way, and be relieved at stated intervals.

They'll serve to keep the curious away, and they'll be there to guard the house in case you three men rush out on a chase or anything like that."

"But--" Verbeck began.