“Safety. It was you who blackmailed Mrs. Ferrars. Who could have had a better knowledge of what killed Mr. Ferrars than the doctor who was attending him? When you spoke to me that first day in the garden, you mentioned a legacy received about a year ago. I have been unable to discover any trace of a legacy. You had to invent some way of accounting for Mrs. Ferrars’s twenty thousand pounds. It has not done you much good. You lost most of it in speculation⁠—then you put the screw on too hard, and Mrs. Ferrars took a way out that you had not expected. If Ackroyd had learnt the truth he would have had no mercy on you⁠—you were ruined forever.”

“And the telephone call?” I asked, trying to rally. “You have a plausible explanation of that also, I suppose?”