ut Audrey kept thinking: "He is
getting nearer to the tank-room." A small staircase led to the attic floor,
upon which were only servants' bedrooms and the tank-room. After he had
mounted this staircase and gone a little way along the passage he swiftly
and without warning dashed back and down the staircase. But nothing seemed
to happen, and he returned. The three doors of the three servants' bedrooms
were all ajar. Mr. Hurley passed each of them with a careless glance
within. At the end of the corridor, in obscurity, was the door of the
tank-room.

"What's this?" he asked abruptly. And he knocked nonchalantly on the door
of the tank-room.

Audrey was acutely alarmed lest Jane Foley should respond, thinking the
knock was that of a friend. She saw how idiotic she had been not to warn
Jane by means of loud conversation with the detective.

"That's the tank-room," she said loudly. "I'm afraid it's locked."

"Oh!" murmured Mr. Hurley negligently, and he turned the searchlight of his
gaze upon the three bedrooms, which he examined as carefully as he had
examined anything in the house. The failure to discover in any cupboard or
corner even the shadow of a human being did not appear to discourage him in
the slightest degree. In the third bedroom--that is to say, the one nearest
the head of the stairs and farthest from the tank-room--he suddenly
beckoned to Audrey, who was standing in the doorway. She went within the
room and he pushed the door to, without, however, quite shutting it.

"Now about the tank-room, Miss Moze," he began quietly. "You say it's
locked?"

"Yes," said the quaking Audrey.

"As a matter of form I'd better just look in. Will you kindly let me have
the key?"

"I can't," said Audrey.

"Why not?"

Audrey acquired tranquillity as she went on: "It's at Frinton. Friends of
mine there keep a punt on Mozewater, and I let them store the sail and
things in the tank-room. There's plenty of room. I give them the key
because that's more satisfactory. The tank-room isn't wanted at all, you
see, while I'm away from home."

"Who are these friends?"

"Mr. and Mrs. Spatt," said Audrey at a venture.

"I see," said the detective.

They came downstairs, and the detective made it known that he would
re-visit the drawing-room. Inspector Keeble followed them. In that room
Audrey remarked:

"And now I hope you're satisfied."

Mr. Hurley merely said:

"Will you please ring for Aguilar?"

Audrey complied. Bu