inger-prints which so exactly corresponded with the ones which we
secured in the flat. How did you obtain them?"

His question non-plussed me.

"I had a suspicion," I replied in a faltering voice, "and I tried to
corroborate it."

"But you have corroborated it," he declared. "Why, Mr. Royle, those
prints you brought to the Yard are a most important clue. Where did you
get them?"

I was silent for a moment, jostled by the crowd of passers-by.

"Well," I said with a faint smile, realising what a grave mistake I had
made in inculpating my well-beloved, "I simply made some experiments as
an amateur in solving the mystery."

"Yes, but those prints were the same as those we got from the flat.
Whence did they come?"

"I obtained them upon my own initiative," I replied, with a forced laugh.

"But you must surely tell me, Mr. Royle," he urged quickly. "It's a most
important point."

"No," I replied. "I'm not a detective, remember. I simply put to the test
a suspicion I have entertained."

"Suspicion of what?"

"Whether my theory was correct or not."

"Whatever theory you hold, Mr. Royle, the truth remains the same. I
truly believe," he said, looking hard at me, "namely that the unknown
victim was struck down by the hand which imprinted the marks you brought
to me--a woman's hand. And if I am not mistaken, sir--you know the
identity of the guilty woman!"

CHAPTER XVII.

CONCERNS MRS. PETRE.

Days, weeks, passed, but I could obtain no further clue. The month of
March lengthened into April, but we were as far as ever from a solution
of the mystery.

Since my return from Brussels I had, of course seen Phrida many, many
times, and though I had never reverted again to the painful subject, yet
her manner and bearing showed only too plainly that she existed in
constant dread!

Her face had become thin and haggard, with dark rings around her eyes and
upon it was a wild, hunted expression, which she strove to disguise, but
in vain.

She now treated me with a strange, cold indifference, so unlike her real
self, while her attitude was one of constant attention and strained
alertness.

The woman Petre had apparently not been approached by Scotland Yard,
therefore as the days went by I became more and more anxious to see her,
to speak with her--and, if necessary, to come to terms with her.

Therefore, without a word to anyone, I one evening caught the six o'clock
train from Liverpool Street, and before eigh