“You don’t think——”

“Dr. Sheppard, I dare to think anything. Ursula Bourne may have killed Mr. Ackroyd, but I confess I can see no motive for her doing so. Can you?”

He looked at me very hard—so hard that I felt uncomfortable.

“Can you?” he repeated.

“No motive whatsoever,” I said firmly.

His gaze relaxed. He frowned and murmured to himself:—

“Since the blackmailer was a man, it follows that she cannot be the blackmailer, then——”

I coughed.

“As far as that goes——” I began doubtfully.

He spun round on me.