usly
considered such a contingency.

"The key had been taken off the bunch?"

"Yes."

"Do the servants know where the key is kept?"

"Some of the maidservants do. The back staircase is occasionally opened
for ventilation and dusting, and the maid who does this work gets the
key from the housekeeper."

"Who has charge of the room where the keys are kept?"

"Nobody in particular. It is really a sort of a lumber-room. The
housekeeper has charge of the keys."

"Thank you; that is all I wish to know."

The butler left the room, and Caldew looked up, to encounter Musard's
eyes regarding him.

"Do you think this has anything to do with the murder?" Musard asked.

Caldew hesitated for a moment. It was on the tip of his tongue to reply
that he attached no importance to the butler's statement, but
professional habits of caution checked his natural impulsiveness.

"I want to know more about the circumstances before advancing an
opinion," he replied. "Tufnell's story was rather vague."

"In what respect?"

"In regard to time. The door may have been left unlocked for days."

"Who would unlock it?" replied Musard. "The inference, in view of what
has happened, seems rather that the door was unlocked to-day, and
Tufnell stumbled upon the fact by a lucky chance--by Fate, if you like.
At least it looks like that to me."

"And the murderer entered by the door?"

"Yes."

"I think that is assuming too much," said Caldew. He had no intention of
pointing out to his companion that such an assumption overlooked the
fact that Tufnell's discovery, and the locking of the door, had not
prevented the crime and the subsequent escape of the murderer.

He turned to leave the room, but Musard was in a talkative mood. He
offered the detective a cigar, and kept him for a while, chatting
discursively. Caldew was in no humour to listen. His mind was full of
the problems of this strange case, and he was anxious to return
upstairs. He took the first opportunity of terminating the conversation
and leaving the room.

It was his intention to conceal himself in one of the wardrobes of the
bedroom in the hope that the owner of the trinket he had found would
return in search of it. As he reached the landing he was surprised to
see that the door of the murdered woman's bedroom was wide open,
although he remembered distinctly that he had closed it when he left the
room to accompany the butler downstairs. With a quickly beating heart he
hurri