such an
atrocious murder? Caldew considered this point long and thoughtfully.
With his keener imagination he differed from Merrington by relying to
some extent on external impressions, and he could not shake off his
first impression of Miss Heredith as a woman of exceptionally good type.
He had to admit to himself that her graciousness and dignity were not
the qualities usually associated with a murderer. Religion, hypocrisy,
smugness, plausibility; these were the commonest counterfeit qualities
of criminals; not dignity, worth, and pride.

There was, of course, the possibility that Miss Heredith, grown
imperious with her long unquestioned sway at the moat-house, had
quarrelled with the young wife, and committed the murder in a sudden
gust of passion. The most unlikely murders had been committed under the
sway of impulse. Caldew recalled that Miss Heredith had been the last
person to see the murdered woman alive, and nobody except herself knew
what had occurred at that interview. It might be that the young wife had
said something to her which rankled so deeply that she conceived the
idea of murdering her.

Caldew, on reaching this stage of his reasoning, shook his head
doubtfully. He had to admit to himself that such a theory did not ring
true. If Miss Heredith had been maddened by some insult at the
afternoon's interview, she was far more likely to have killed Mrs.
Heredith immediately than have waited until dinner-time. And, if she had
committed the murder, why had she gone about it in the manner likeliest
to lead to discovery, openly leaving her guests a few minutes before,
and allowing herself to be seen afterwards descending the staircase?
Even the veriest neophyte in crime usually displayed some of the caution
of self-preservation.

But Caldew was too experienced in criminal investigation to reject a
theory merely because it was contrary to experience. There existed
presumptions for suspicion of Miss Heredith which at least warranted
further inquiry. And, thinking over these presumptions, he arrived at
the additional conclusion that the theory of her guilt could also be
made to account for the puzzle of the open window in Mrs. Heredith's
bedroom. Caldew believed that the open window had some bearing on the
crime. His first impression had been that the murderer had entered and
escaped by that means. The Virginia creeper to which Weyling had
directed attention that morning had strengthened that belief, in spite