gs frowned and took out the knife at which he looked. "She knows
a good deal about this affair," he murmured. "Who is she shielding? I
suspect her brother. Otherwise she would not have hidden the knife. I
wonder to whom it belongs. Here are three notches cut in the
handle--there is a stain on the blade--blood, I suppose."

He got no further in his soliloquy, for Mrs. Octagon swept into the
room in her most impressive manner. She was calm and cool, and her
face wore a smile as she advanced to the detective. "My dear Mr.
Jennings," she said, shaking him warmly by the hand, "I am so glad to
see you, though I really ought to be angry, seeing you came to my house
so often and never told me what you did."

"You mightn't have welcomed me had you known," said he dryly.

"I am above such vulgar prejudices," said Mrs. Octagon, waving her hand
airily, "and I am sure your profession is an arduous one. When Juliet
told me that you were looking into this tragic death of my poor sister
I was delighted. So consoling to have to do with a gentleman in an
unpleasant matter like this. Why have you come?"

This last question was put sharply, and Mrs. Octagon fastened her big
black eyes on the calm face of the detective. "Just to have a look at
the house," he said readily, for he was certain Juliet would not report
their conversation to her mother.

Mrs. Octagon shrugged her shoulders. "A very nice little house, though
rather commonplace in its decoration; but my poor sister never did have
much taste. Have you discovered anything likely to lead to the
discovery of her assassin?"

"I am ashamed to say I am quite in the dark," replied Jennings. "I
don't suppose the truth will ever be discovered."

The woman appeared relieved, but tried to assume a sad expression.
"Oh, how very dreadful," she said, "she will lie in her untimely grave,
unavenged. Alas! Alas!"

But Jennings was not mystified by her tragic airs.

He was certain she knew something and feared lest it should come to his
knowledge. Therefore he resolved to startle her by a blunt question.
"I never knew you were acquainted with Maraquito!"

Mrs. Octagon was not at all taken aback. "I don't know such creatures
as a rule," she said calmly. "What makes you think I do?"

"I saw you enter her house one night."

"Last night," said Mrs. Octagon coolly. "Yes. Maraquito, or Senora
Gredos, or whatever she calls herself, told me you had just gone. I
saw her in