Kirby thought he heard the whisper of voices and he knocked again.  He had to rap a third time before the door was opened.

“What is it?  What do you want?”

If ever Lane had seen stark, naked fear in a human face, it stared at him out of that of the woman in front of him.  She was a tall, angular woman of a harsh, forbidding countenance, flat-breasted and middle-aged.  Behind her, farther back in the room, the roughrider caught a glimpse of a fat, gross, ashen-faced man fleeing toward the inner door of a bedroom to escape being seen.  He was thrusting into his coat pocket what looked to the man in the hall like a revolver.

“Can you tell me where James Cunningham’s apartment is?” asked Kirby.

The woman gasped.  The hand on the doorknob was trembling violently.  Something clicked in her throat when the dry lips tried to frame an answer.

“Head o’ the stairs—­right hand,” she managed to get out, then shut the door swiftly in the face of the man whose simple question had so shocked her.

Kirby heard the latch released from its catch.  The key in the lock below also turned.

“She’s takin’ no chances,” he murmured.  “Now I wonder why both her an’ my fat friend are so darned worried.  Who were they lookin’ for when they opened the door an’ saw me?  An’ why did it get her goat when I asked where Uncle James lived?”

As he took the treads that brought him to the next landing the cattleman had an impression of a light being flashed off somewhere.  He turned to the right as the woman below had directed.

The first door had on the panel a card with his uncle’s name.  He knocked, and at the same instant noticed that the door was ajar.  No answer came.  His finger found the electric push button.  He could hear it buzzing inside.  Twice he pushed it.

“Nobody at home, looks like,” he said to himself.  “Well, I reckon I’ll step in an’ leave a note.  Or maybe I’ll wait.  If the door’s open he’s liable to be right back.”

He stepped into the room.  It was dark.  His fingers groped along the wall for the button to throw on the light.  Before he found it a sound startled him.

It was the soft faint panting of some one breathing.

He was a man whose nerves were under the best of control, but the cold feet of mice pattered up and down his spine.  Something was wrong.  The sixth sense of danger that comes to some men who live constantly in peril was warning him.

“Who’s there?” he asked sharply.

No voice replied, but there was a faint rustle of some one or some thing stirring.

He waited, crouched in the darkness.

There came another vague rustle of movement.  And presently another, this time closer.  Every sense in him was alert, keyed up to closest attention.  He knew that some one, for some sinister purpose, had come into this apartment and been trapped here by him.