you left⁠—as you were standing beside his chair? Then you go out of the front door, run round to the summerhouse, take Ralph Paton’s shoes out of the bag you brought up with you that night, slip them on, walk through the mud in them, and leave prints on the window ledge, you climb in, lock the study door on the inside, run back to the summerhouse, 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?”