"A little before six—perhaps a quarter of an hour."

"Is it your custom to try this door every night?"

"Oh, no, it is not necessary. The door is always kept locked, and the key hangs with a bunch of other unused keys in a small room near the housekeeper's apartments, where a number of odds and ends are kept."

"When was the last time you tried the door?"

The butler considered for a moment.

"I cannot rightly say," he said at length. "The door is never used, and I rarely think of it."

"Then, for all you know to the contrary, the key may have been in the door for days, or weeks past."

"Why, yes, it is possible, now that you come to mention it," said the butler, with an air of surprise, as though he had not previously considered such a contingency.

"The key had been taken off the bunch?"

"Yes."