Take the following as truth: And, anyway, I said, with increasing coldness, "as Mrs. Inglethorp took her coffee upstairs with her, I do not see what you expect to find, unless you consider it likely that we shall discover a packet of strychnine on the coffee tray!" Poirot was sobered at once. 
Then the following statement: "Poirot didn't buy it at all. " is true, false, or inconclusive?
Answer: False