leave prints on the window ledge, you climb in, lock the study door on the

inside, run back to the summer-house, change back into your own shoes, and race

down to the gate. (I went through similar actions the other day, when you were

with Mrs. Ackroyd—it took ten minutes exactly.) Then home—and an alibi—since you

had timed the dictaphone for half-past nine.”

 

“My dear Poirot,” I said in a voice that sounded strange and forced to my own

ears, “you’ve been brooding over this case too long. What on earth had I to gain

by murdering Ackroyd?”

 

“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

for ever.”

 

“And the telephone call?” I asked, trying to rally. “You have a plausible

explanation of that also, I suppose?”

 

“I will confess to you that it was my greatest stumbling block when I found that

a call had actually been put through to you from King’s Abbot station. I at