The cook, who knew me when I was a schoolboy, sleeps alone; all three servants sleep on the floor above.

I locked the jewels up in the safe which stands in the dressing-room.

My keys and watch I placed, as usual, beside my bed.

As a rule, I am a fairly light sleeper.
"'I cannot understand how it could have happened--but--you had better come up and have a look at the safe.

The key must have been abstracted from my bedside, the safe opened, and the keys replaced--all while I was fast asleep.