It might have been cleaned and oil smeared upon it
after the commission of the crime. Yet as far as I could discern with
the naked eye there was no evidence that it had recently been used.

It was the man's curious apprehensive glance that had first aroused my
suspicion, and the admissions that he had opened the back door, and
that he had been armed, both increased my mistrust. The detectives,
too, were interested in the weapon, but were soon satisfied that,
although a dangerous knife, it bore no stain of blood.

So I put it back in its case and replaced it. But I experienced some
difficulty in getting the loop of wire back upon the brass-headed nail
from which it was suspended; and it then occurred to me that Short, in
the excitement of the discovery, and ordered by Ethelwynn to go at
once in search of me, would not without some motive remain there,
striving to return the knife to its place. Such action was unnatural.
He would probably have cast it aside and dashed out in search of a
cab. Indeed, the constable on the beat had seen him rush forth
hurriedly and, urged by Ethelwynn, run in the direction of Kew Bridge.

No. Somehow I could not rid myself of the suspicion that the man was
lying. To my professional eye the weapon with which the wound had been
inflicted was the one which he admitted had been in his possession.

The story that he had unlocked the door and gone in search of the
assassin struck the inspector, as it did myself, as a distinctly lame
tale.

I longed for the opening of the telegraph office, so that I might
summon my friend Jevons to my aid. He revelled in mysteries, and if
the present one admitted of solution I felt confident that he would
solve it.

CHAPTER VIII.

AMBLER JEVONS IS INQUISITIVE.

People were about me the whole time. Hence I had no opportunity of
re-examining the little object I had picked up from the spot where the
murderer must have stood.

When morning dawned two detectives from Scotland Yard arrived, made
notes of the circumstances, examined the open window in the
conservatory, hazarded a few wise remarks, and closely scrutinised the
dagger in the hall.

Ethelwynn had taken her sister to a friend in the vicinity,
accompanied by the nurse and the cook. The house was now in the
possession of the police, and it had already become known in the
neighbourhood that old Mr. Courtenay was dead. In all probability
early passers-by, men on their way to work, had noticed