"Not even then. Of course I didn't know the explanation of that, and at once set about finding one. Fuller was put to work looking up Bohlmier, and in one day had his record complete. The man is a skilful blackmailer; he has practiced in many cities and has served more than one term in jail. I knew at once what had occurred; the two men fancied they 'had something on' Miss Cavanaugh regarding this murder, and had endeavored to extort money from her. I leave it to you," with a smiling nod toward Nora, "to tell how near I am to the facts."

The girl made a low-voiced, unintelligible reply, and then they ran on for some distance in silence. Suddenly Ashton-Kirk signaled the driver and the car came to a stand; the investigator pointed to some buildings at no great distance; a locomotive with a few cars trailing behind it was panting laboriously away from these, its headlight glaring morosely into the darkness.

"I think," said the investigator, "that is Stanwick Station."

"It is," agreed Scanlon.

"Then, more than likely, that is the train which carried Fenton and Fuller. I suppose it would be as well if we got out here and walked the remainder of the way."

Accordingly they alighted, and the driver was instructed to wait where he was. Then they proceeded toward Duncan Street, reaching which they turned into it, and soon were in the neighborhood of No. 620. They paused in the shadows in which Bat Scanlon had spoken to the old resident; the house opposite seemed dark and silent.

"No one stirring," said Bat. "This whole section can be as quiet a place as I know of when it takes the notion."

Ashton-Kirk, who had been straining his eyes through the darkness, now placed his fingers to his lips and gave a peculiar whistle. After a moment there was an answer to this, and then a figure emerged from the shadow of the Burton house. In a very little while longer Fuller crossed the street to them.

"What news?" asked the investigator, briefly.

"Fenton is in the house," answered Fuller. "I followed him from the train; he went to the front door, rang in the regular way and was admitted by what looked to me to be a nurse."

"Had he any idea he was followed?"

"I think not. He made no show of it, anyhow."

"Suppose you stay here and keep Mr. Quigley company for a few minutes,"

suggested Ashton-Kirk. "We'd like to look around a bit."

"I am not accustomed to the night air," complained the broker. "It has a bad effect upon my breathing."

"We shall be only a very little while," he was a.s.sured.

Ashton-Kirk crossed the street with Nora and Scanlon at his side.

Quietly they entered at the little iron gate and stood for a s.p.a.ce examining the house.

From the fan light above the front door came a dull glow, as though a subdued light burned in the hall.

"All the shutters are closed," said Bat, as he noticed this fact. "They may be brightly lighted inside and we not know it."

The keen, searching eyes of Ashton-Kirk caught a sort of glow upon the gra.s.s at one side; he moved in that direction and the others followed him. At the second floor a light flickered dimly in a window; it was a wavering, uncertain sort of thing, and Bat Scanlon recognized it at once.

"It's candle-light," said he. "Remember, I told you about seeing the girl----"

Here he felt Nora's cold hand close upon his wrist; at the window appeared the figure of Mary Burton, in the same loose gown as before and holding a candle in her hand. The light was full upon her face as she bent forward as though intent upon catching some sound. And the face was white and rigid with fear.

"Have you looked through the upper part of the house?" Ashton-Kirk asked Scanlon.

"No," replied Bat.

"I have," said the other. "That window is right at the head of a stairway. Something is being said or done upon the lower floor which rather upsets her."

He moved forward as he spoke; beneath the dimly-lighted window above was a square, heavily made shutter different from the others in shape, and marking a hall window. As they were about to pa.s.s it, Ashton-Kirk uttered a low exclamation and stopped suddenly. The shutter was badly fitted, having swollen with the weather, so that it could not be completely closed. The slim, strong fingers of Ashton-Kirk gripped its edge; slowly, carefully, with never a creak it opened. There was a white curtain inside, but a pendant light made all things in the hall visible.

A flight of stairs led to the second floor, and at the foot of these stood Fenton, one hand upon the rail, and the nurse, with frightened face, was pleading with him, as though not to do something which he had signified his intention of doing.

"Ah!" Scanlon heard Ashton-Kirk breathe. "So that's your game, is it?"

Then to Bat: "Stay here; keep an eye on that fellow, and be ready to act."

With these words he slipped easily away into the darkness, and Scanlon and Nora were left alone at the window.

"He is demanding to be allowed to see Mary," said the trembling voice of Nora in Bat's ear. "And the poor nurse is terrified. See how she tries to stop him!"

With a sort of snarl, the broken-nosed man threw off the detaining hand of the nurse and turned a threatening face upon her, at the same time gesturing toward the upper floor and signifying his intention of ascending in spite of anything the girl might say.

"But she's got grit," said Bat, in a low tone of admiration. "She hangs to him. The girl up-stairs is her patient, and she'll not have her frightened. It's part of the training they get, I guess."

Fenton let go the stair rail and made a step toward the nurse; his ugly face was distorted, and his hands were clenched. He began to speak; what he said could not be heard by the watchers outside the window, but the nurse seemed terrified and shrank from him.

"He's down to cases now," said Scanlon, as he deftly freed his revolver, and held it ready, but in such a way that Nora could not see it.

"Look!" whispered Nora, thrillingly. "Look, Bat. On the stairs!"

Bat Scanlon shifted his eyes from the threatening figure of Fenton, and the shrinking one of the nurse; upon the stairs, coming slowly down, her loose dressing-gown held about her by one slim hand, was Mary Burton.

She had reached the foot of the stairs before the broken-nosed man saw her; then he whirled about, and his hands gripped her delicate throat.

Scanlon's revolver arose to a deadly level, but before he could fire, Ashton-Kirk was seen to leap into the hall like a panther. There was a short, sharp blow, with all the power of the lithe body behind it; Fenton's grasp relaxed and he fell to the floor. The watchers saw Mary totter, and noted Ashton-Kirk catch her in his arms, at the same time gesturing to the nurse to bring a restorative. The nurse had vanished, and Ashton-Kirk was placing the sick girl upon a hall lounge when Nora and Scanlon hurried from the window and around to the door.

This stood wide open, and they encountered Fuller and the p.a.w.nbroker, Quigley, as they entered. In the hall they saw Fenton rising sullenly to his feet, one hand feeling at his jaw; Ashton-Kirk was bending over the white, fragile creature upon the lounge.

"There she is," said Scanlon, pointing to Mary and looking at Quigley.

"There she is. Pile it all on her shoulders. She's strong and can stand it. Say your say, and then beat it; for by George, I won't be able to stand the sight of you afterward."

Quigley looked at the speaker in surprise; then his puffy eyes went to Mary with a deepening of their astonishment, and finally to Ashton-Kirk.

"Is this the lady you had in mind?" said he. "If so you have made a mistake. She is not the person who sold me the diamonds."

Nora Cavanaugh gave a gasping sort of cry and stood staring at the p.a.w.nbroker, her wide eyes full of joy--of bewilderment. At that moment a set of hangings were pushed aside and the nurse came into the hall, a gla.s.s in her hand. Silently Ashton-Kirk touched Quigley upon the arm, and pointed to the nurse. The man started, and then regarded her intently.

"Yes," said he. "Yes! That is the woman! I can take my oath on that in any court in the land."

The woman stood motionless for a moment; she drew in a long breath; the gla.s.s fell to the floor and smashed. Then she disappeared once more through the door by which she entered.

"Fuller," said Ashton-Kirk. But he had no need to speak, for that brisk young man was already after her. Dazed, Bat Scanlon looked about. Nora was upon her knees beside the sick girl, sobbing and chafing her pale hands; the investigator was at a telephone summoning the police.

Scanlon's glance then wandered to Fenton, and there rested.

"You told us a couple of hours ago," said he, "that a woman killed Tom Burton and that you saw her do it. Has he," and he nodded toward Quigley, "got it on the right party?"

"Yes," replied the broken-nosed man, "he's got it right; it was the nurse. You don't have to look any further than that."

"But," said Bat, a last doubt in his mind, "what was the idea of you wanting to go up-stairs a while ago, if you didn't want her?" pointing to Mary.

"It was the sparks I wanted," said Fenton. "I thought if any were left they were in the nurse's room."