Deadly Nightcap — Harry Carmichael

Mrs. Esther Payne was a very unpopular lady - right up to the night when she took two sleeping tablets and died. Sleeping tablets don't kill, nor does hate - even so much of it - but when traces of strychnine were discovered in the tube of pills that had lulled her to her last, long sleep, it seemed that hate had found a way. Of motive there was plenty, but four people only had the opportunity to obtain the poison for Esther's deadly night-cap.