Lane and his friend stepped out to the platform of the fire escape.  Below them was the narrow alleyway, directly in front the iron frame of the Wyndham fire escape.

A discovery flashed across Kirby’s brain and startled him.  “See here, Cole.  If a man was standin’ on that platform over there, an’ if my uncle had been facin’ him in a chair, sittin’ in front of the window, he could ‘a’ rested his hand on that railin’ to take aim an’ made a dead-center shot.”

Cole thought it out.  “Yes, he could, if yore uncle had been facin’ the window.  But the chair wasn’t turned that way, you told me.”

“Not when I saw it.  But some one might ‘a’ moved the chair afterward.”

The champion of the world grinned.  “Seems to me, old man, you’re travelin’ a wide trail this trip.  If some one tied up the old man an’ chloroformed him an’ left him here convenient, then moved him back to the wall after he’d been shot, then some one on the fire escape could ‘a’ done it.  What’s the need of all them ifs?  Since some one in the room had to be in the thing, we can figure he fired the shot, too, whilst he was doin’ the rest.  Besides, yore uncle’s face was powder-marked, showin’ he was shot from right close.”

“Yes, that’s so,” agreed Lane, surrendering his brilliant idea reluctantly.  A moment, and his face brightened.  “Look, Cole!  The corridor of that hotel runs back from the fire escape.  If a fellow had been standin’ there he could ‘a’ seen into the room if the blind wasn’t down.”

“Sure enough,” agreed Sanborn.  “If the murderer had give him an invite to a grand-stand seat.  But prob’ly he didn’t.”

“No, but it was hot that night.  A man roomin’ at the Wyndham might come out to get a breath of air, say, an’ if he had he might ‘a’ seen somethin’.”

“Some more of them ifs, son.  What are you drivin’ at, anyhow?”

“Olson.  Maybe it was from there he saw what he did.”

Sanborn’s face lost its whimsical derision.  His blue eyes narrowed in concentration of thought.  “That’s good guessin’, Kirby.  It may be ’way off; then again it may be absolutely correct.  Let’s find out if Olson stayed at the Wyndham whilst he was in Denver.  He’d be more apt to hang out nearer the depot.”

“Unless he chose the Wyndham to be near my uncle.”

“Mebbeso.  But if he did it wasn’t because he meant the old man any good.  Prove to me that the Swede stayed there an’ I’ll say he’s as liable as Hull to be guilty.  He could ‘a’ throwed a rope round that stone curlycue stickin’ out up there above us, swung acrost to the fire escape here, an’ walked right in on Cunningham.”

Lane’s quick glance swept the abutment above and the distance between the buildings.

“You’re shoutin’, Cole.  He could ‘a’ done just that.  Or he might have been waitin’ in the room for my uncle when he came home.”

“Yes.  More likely that was the way of it’—­if we’re on a hot trail a-tall.”