put his boots outside his door to be cleaned, but came to the door with
them in his hand in the morning. But Penreath told me this morning that
he put out his boots overnight to be cleaned, but had taken them back
into his room before Ann brought up his tea. The murderer, therefore,
had ample opportunity to use them for his purpose of carrying the body
to the pit and to put them back afterwards outside Penreath's door.

"But Peggy's belated admissions did more than suggest that Penreath was
the victim of a sinister plot--they narrowed down the range of persons
by whom it could have been contrived. The plotter was not only an inmate
of the inn, but somebody who had seen the match box and knew that it
belonged to Penreath.

"I returned to Flegne to resume the investigations I had broken off
nearly three weeks before, and from that point my discoveries were very
rapid, all tending to throw suspicion on Benson. The first indication
was the outcome of a remark of mine about his height, and the broken gas
light in Mr. Glenthorpe's bedroom. It was purely a chance shot, but it
threw him into a pitiable state of excitement. I let him think, however,
that it was nothing more than a chance remark. That night I was put to
sleep in Penreath's room, and there I made two discoveries. The first
was the existence of a small door, behind the wardrobe, opening on a
corresponding door on the other side, which in its turn opens into Mr.
Glenthorpe's room. Thus it would be possible for a person in the room
Penreath occupied, discovering these doors as I did, to see into the
next bedroom--under certain conditions. My second discovery was the
outcome of my first discovery--I picked up underneath the wardrobe a
fragment of an appealing letter which Penreath had commenced to write to
his fiancee, and had subsequently torn up. It was a long time before I
grasped the full significance of these two discoveries. Why should a
man, after writing a letter of appeal to his fiancee, decide not to send
it and destroy it? The most probable reason was that something had
happened to cause him to change his mind. What could have happened to
change the conditions so quickly? The hidden doors in the wall, which
looked into the next room, supplied an answer to the question. Penreath
had looked through, and seen--what? My first thought was that he had
seen the murder committed, but that theory did not account for the
destruction of the letter, and his silence w