d it back to its first
source--Cotherstone. Brereton was a close observer of men; it was his
natural instinct to observe, and he was always giving it a further
training and development. He had felt certain as he sat at supper with
him, the night before, that Cotherstone had something in his thoughts
which was not of his guests, his daughter, or himself. His whole
behaviour suggested pre-occupation, occasional absent-mindedness: once
or twice he obviously did not hear the remarks which were addressed to
him. He had certainly betrayed some curious sort of confusion when
Kitely's name was mentioned. And he had manifested great astonishment,
been much upset, when Garthwaite came in with the news of Kitely's
death.

Now here came in what Brereton felt to be the all-important, the
critical point of this, his first attempt to think things out. He was
not at all sure that Cotherstone's astonishment on hearing Garthwaite's
announcement was not feigned, was not a piece of pure acting. Why? He
smiled cynically as he answered his own question. The answer
was--_Because when Cotherstone, Garthwaite, Bent, and Brereton set out
from Cotherstone's house to look at the dead man's body, Cotherstone led
the way straight to it_.

How did Cotherstone know exactly where, in that half-mile of wooded
hill-side, the murder had been committed of which he had only heard five
minutes before? Yet, he led them all to within a few yards of the dead
man, until he suddenly checked himself, thrust the lantern into
Garthwaite's hands and said that of course he didn't know where the body
was! Now might not that really mean, when fully analyzed, that even if
Cotherstone did not kill Kitely himself during the full hour in which
he was absent from his house he knew that Kitely had been killed, and
where--and possibly by whom?

Anyway, here were certain facts--and they had to be reckoned with.
Kitely was murdered about a quarter-past nine o'clock. Cotherstone was
out of his house from ten minutes to nine o'clock until five minutes to
ten. He was clearly excited when he returned: he was more excited when
he went with the rest of them up the wood. Was it not probable that
under the stress of that excitement he forgot his presence of mind, and
mechanically went straight to the all-important spot?

So much for that. But there was something more. Mallalieu was
Cotherstone's partner. Mallalieu went to Northrop's house to play cards
at ten o'clock. It might be w