Drawing himself up, he became a thin shape that stood motionless beside the door.
Mayhew shook himself and stretched. He glanced toward each door, shifted his position in his chair, and examined his cigar, which was commencing to come apart.
The detective grunted as he tried to repair the remains of the cigar.
While he was thus occupied, he failed entirely to observe what happened at the door to the study.
The Shadow moved over to cover the door. While his body blotted out the barrier, his black-gloved hand inserted a key in the lock. The slight clicking was muffled beneath the covering cloak.
The door opened inward — not more than a foot. The Shadow slipped into the study, and the door closed softly.
Perhaps it was a slight sound that attracted Mayhew’s attention. The detective looked suddenly toward the door an instant after it had shut. He went to the door and listened.
There was no sound from the inner room. Mayhew went back to his chair.
Absolute darkness pervaded the room in which Silas Harshaw had been slain. It seemed like a chamber of death. Not a single sound disturbed the sinister silence. Yet, there was motion in that room.
A man who was an integral part of the darkness was moving here and there. A tiny ray of light appeared at intervals. It illuminated the old man’s desk. It shone upon the bits of sculpture in the corner.
It rested on the chess board. It revealed the gas heater at the inner end of the room.
Only the reappearing light betokened the movement of the man who carried it. The gleaming spot came and went in haphazard fashion, arriving in the most unexpected places.
It disappeared for a full minute, then flickered in the bedroom that adjoined the study.
At last, it was back in the large room. It shone on the floor — at the very place where Silas Harshaw’s dead body had been found.
The silvery radiator glittered as the light ran along it. Then the gleaming torch made a small spot that zigzagged along the sill.
It disappeared and left no trace. The Shadow had returned to the gloom of the room.
Now he was below the window sill, a crouching figure, stooping as Silas Harshaw might have stooped, the night he met his doom.
For one fraction of a second, the light again glimmered on the floor. Then it was no longer visible.
The cause of its disappearance was a muffled sound that had occurred outside the window.
There was a slight crackling; the noise of metal driven into wood. The Shadow arose and stood beside the window.
SOME one was moving against the iron grating!
The window was a dim frame that provided very little relief from the blackness of the room, but now the vague outline of a man was visible there.
The sash had been left raised, exactly as it had been found by the police. Hence, a cautious, metallic noise was audible in the room.
The man who was working at the grating was a craftsman in his own line of endeavor. He was loosening the grating in expert fashion. Even when the iron barrier swung wide, its squeaks were repressed.
His difficult task accomplished, the man outside pressed himself through the window. He crawled along the sill, and as he did so, The Shadow drew back toward the nearest corner.
The man in black stood motionless, but his gloved hand gripped the handle of a hidden automatic.
The stranger had entered the room. He was crouched by the window sill. He remained there, listening. Several minutes elapsed before the newcomer was sure that all was well. His breathing, restrained though it was, made a wheezing sound in the darkness.
It was a marked contrast to the silence in the corner where The Shadow stood. No noise whatever came from that quarter.
Now a flashlight shone. It was turned toward the floor, and its bright circle reflected upward to show a huddled, stocky form.
Even in that dim surrounding, the man at the window might have been recognized as the one who had left the lobby after Joe Cardona had departed.
The light swung inward, and pointed at an angle along the floor. The increasing luminosity must have made the man fear it would betray his presence, for he clicked off the light.
He was cautious for a short time; then, again, the flashlight gleamed, but it was turned away from the room. It showed the floor and the base of the radiator.
It moved upward and went out as it began to shine on the edge of the window sill.
Silence reigned, but there was motion by the window sill. The man there was occupied in some mysterious work. He was totally oblivious of the presence of The Shadow. He did not know that a menacing form stood close by, with a loaded automatic in readiness.
The crouching man breathed quickly and eagerly. His lips were forming soft, incoherent words. A low exclamation — hardly more than a whisper — was uttered by him.
Then came the sound of a pistol shot.
It was a muffled report that seemed to be absorbed by the room itself. A wailing, gasping cry came from the window sill. A long groan followed.
This succession of startling sounds could hardly have been heard on the floors below, but they could not escape the listening ears of any one within the apartment.
A chair overturned in the outer room. Mayhew’s police whistle shrilled.
The latch of the door clicked. The door opened. Mayhew pressed the light switch, and leaped into the illuminated room, revolver in hand. The detective sergeant stared in profound amazement.
Stretched upon the floor by the window lay the body of a man.
Face upward, arms sprawled, it might have been the form of Silas Harshaw, for it lay exactly as the body of the old man had lain.
The second victim had been slain within the walls of this mysterious room!
CHAPTER VI
DEATH UNEXPLAINED
STANDING in the doorway of the study, Detective Sergeant Mayhew gazed quickly about the room in search of an unknown enemy.
There was murder here — but where was the man who had committed the crime? Mayhew spied the open window. Even as he thought of it as an avenue for escape, he heard the strident treble of a whistle from the courtyard beneath.
Then came a banging at the outer door of the apartment. Mayhew hurried in that direction. A plainclothes man entered.
“Two patrolmen coming up,” he explained. “I was out front. Heard your whistle. What’s happened?”
“Stay right here,” ordered Mayhew. “Watch this door. There’s been a murder!”
He rushed into the study and hastened to the window. He leaned across the sill, and gazed downward into the glare of a powerful electric lantern.
Mayhew’s hands pressed against metal hooks, and he saw a collapsible ladder hanging beneath him.
“Hey — Mayhew!”
It was Cardona’s voice from the courtyard. Detective Sergeant Mayhew shouted in response.
“Any one come down this way?”
“No,” cried Cardona. “I’ve been here five minutes. Thought I saw something that looked like a ladder up on the wall. Kept the glimmer off it. Was there a shot?”
“Yes!” shouted Mayhew. “The man must still be here! I have help!”
“We’ll cover from down here,” answered Cardona.
Mayhew slipped back into the room. He hastened to find the man who was guarding the door.
“Stay posted here,” said Mayhew grimly. “There’s a dead man in the other room. The killer couldn’t have gotten out by the window. I’ll look for him. Send the patrolmen in when I call.”
In the study, Mayhew looked about him. There was no place where a man could hide. It was impossible for the second man to have escaped by the window.
Yet there must have been a slayer, for there, almost at Mayhew’s feet, lay the dead man, shot through the heart.