. The shade hung an inch or two from
the window frame, so that by holding his eye close he could get more
than a glimpse of the interior.

He tapped gently on the glass. The lights inside flashed on. From one
viewpoint he could see almost half the room. He could go to the other
side of the blind and see most of the other half.

A man sat down in a chair close to the opposite wall, letting his hands
fall on the arms. A girl stood in front of him and pointed a
paper-knife at his head, holding it as though it were a revolver. The
head of the man fell sideways.

Kirby tapped on the window pane again. He edged up the sash and
stepped into the room.

The young woman turned to him eagerly, a warm glow in her shell-pink
cheeks. "Well?" she inquired.

"Worked out fine, Rose," Kirby said. "I could see the whole thing."

"Still, that don't prove anything," the other man put in. He belonged
to the staff of the private detective agency with which Kirby was
dealing.

The Wyoming man smiled. "It proves my theory is possible. Knowing
Olson, I'm willin' to gamble he didn't sit still on the fire escape an'
let that drawn blind shut him off from what was goin' on inside. He
was one mighty interested observer. Now he must 'a' known there was a
clothes-line on the roof. From the street you can see a washin'
hangin' out there any old time. In his place I'd 'a' bopped up to the
roof an' got that line. Which is exactly what he did, I'll bet. The
line had been tied to the posts with a lot of knots. He hadn't time to
untie it. So he cut the rope. It's been spliced out since by a piece
of rope of a different kind."

"How do you know that's been done since?" the detective asked.

"A fair question," Kirby nodded. "I don't. I'll find out about that
when I talk with the landlady of the Wyndham. If I'm right you can bet
that cut rope has puzzled her some. She can't figure out why any one
would cut her rope down an' then leave it there."

"If you can show me her rope was cut that night, I'll say you're
right," the detective admitted. "And if you are right, then the Swede
must 'a' been right here when your uncle was killed."

"_May_ have been," Kirby corrected. "We haven't any authentic evidence
yet as to exactly when my uncle was killed. We're gettin' the time
narrowed down. It was between 9.30 and 9.50. We know that."

"How do you know that?" the professional sleuth asked. "Accordin' to
your story you didn