“Quite sure. I was uncertain whether to wear them or not, but in the end I decided on the emeralds, and put them back in the jewel-case.”

“Who locked up the jewel-case?”

“I did. I wear the key on a chain round my neck.” She held it up as she spoke.

The inspector examined it, and shrugged his shoulders.

“The thief must have had a duplicate key. No difficult matter. The lock is quite a simple one. What did you do after you’d locked the jewel-case?”

“I put it back in the bottom drawer where I always keep it.”

“You didn’t lock the drawer?”

“No, I never do. My maid remains in the room till I come up, so there’s no need.”

The inspector’s face grew graver.