“How do you know?” I inquired stupidly.

“We have searched the rooms and personal belongings of each of those present at that dinner party last Thursday night.”

“What!”

“In fact, I daresay that there is not a room in the whole of St. Ann’s, as well as in the Letheny cottage, that has not been thoroughly ransacked.”

I ran my tongue over dry lips. This was getting down to work with a vengeance.

“Why?” I stammered.

There was a glimmer of impatience in his eyes.

“For the radium, of course. Surely you did not think we were going to let it get away from us without a struggle.”

There was a moment or two of silence during which I studied the polished glass surface of the desk before me without seeing it.

“Did you ask Huldah about Miss Letheny’s errand through the rain last Friday afternoon?” inquired O’Leary after a contemplative pause.