r a moment, then set his teeth hard, so that his jaw
muscles stood out prominently under the pallid skin.

"What do you want to know, then?" asked Exel.

"I will be wanting to know," said Dunbar, "where you were coming from,
to-night?"

"From the House of Commons."

"You came direct?"

"I left Sir Brian Malpas at the corner of Victoria Street at four
minutes to twelve by Big Ben, and walked straight home, actually
entering here, from the street, as the clock was chiming the last stroke
of midnight."

"Then you would have walked up the street from an easterly direction?"

"Certainly."

"Did you meet any one or anything?"

"A taxi-cab, empty--for the hood was lowered--passed me as I turned the
corner. There was no other vehicle in the street, and no person."

"You don't know from which door the cab came?"

"As I turned the corner," replied Exel, "I heard the man starting his
engine, although when I actually saw the cab, it was in motion; but
judging by the sound to which I refer, the cab had been stationary,
if not at the door of Palace Mansions, certainly at that of the next
block--St. Andrew's Mansions."

"Did you hear, or see anything else?"

"I saw nothing whatever. But just as I approached the street door, I
heard a peculiar whistle, apparently proceeding from the gardens in the
center of the square. I attached no importance to it at the time."

"What kind of whistle?"

"I have forgotten the actual notes, but the effect was very odd in some
way."

"In what way?"

"An impression of this sort is not entirely reliable, Inspector; but it
struck me as Oriental."

"Ah!" said Dunbar, and reached out the long arm for his notebook.

"Can I be of any further assistance?" said Exel, glancing at his watch.

"You had entered the hall-way and were about to enter your own flat when
the voices of Dr. Cumberly and Mr. Leroux attracted your attention?"

"I actually had the key in my hand," replied Exel.

"Did you actually have the key in the lock?"

"Let me think," mused Exel, and he took out a bunch of keys and dangled
them, reflectively, before his eyes. "No! I was fumbling for the right
key when I heard the voices above me."

"But were you facing your door?"

"No," averred Exel, perceiving the drift of the inspector's inquiries;
"I was facing the stairway the whole time, and although it was in
darkness, there is a street lamp immediately outside on the pavement,
and I can swear, positively, that no