“Somebody came in that way,” I suggested.
“Possibly,” agreed Poirot, but he spoke absently and without conviction. After a minute or two he said:
“That is not exactly the point I had in mind, Hastings. If only one window was open it would not intrigue me so much. It is both windows being open that strikes me as curious.”
He hurried into the other room.
“The sitting-room window is open, too. That also we left shut. Ah!”
He bent over the dead man, examining the corners of the mouth minutely. Then he looked up suddenly.
“He has been gagged, Hastings. Gagged and then poisoned.”
“Good heavens!” I exclaimed, shocked. “I suppose we shall find out all about it from the postmortem.”
“We shall find out nothing. He was killed by inhaling strong prussic acid. It was jammed right under his nose. Then the murderer went away again, first opening all the windows. Hydrocyanic acid is exceedingly volatile, but it has a pronounced smell of bitter almonds. With no trace of the smell to guide them, and no suspicion of foul play, death would be put down to some natural cause by the doctors. So this man was in the Secret Service, Hastings. And five years ago he disappeared in Russia.”
“The last two years he’s been in the Asylum,” I said. “But what of the three years before that?”
Poirot shook his head, and then caught my arm.
“The clock, Hastings, look at the clock.”