Alfred Inglethrop is the main antagonist of Agatha Christie 1920 novel, The Mysterious Affair at Styles, which was her first published novel and the debut of Hercule Poirot.
He was portrayed by Michael Cronin in the 1990 television film adaptation from Agatha Christie's Poirot, and was voiced by Hugh Dickson in the 2005 radio adaptation of BBC 4 Radio.
Alfred Inglethrope is Emily Inglethorp's second husband and a much younger man than her, being considered by her family to be a spoiled fortune-hunter. However, he was secretly in love with Evelyn Howard and murdered his wife so that they could be together.
After Emily discovered that her eldest stepson, John Cavendish, had a love affair, she began a fiery arguement with him and changed her will. However, she later discovered that Alfred had a love affair with Evelyn as well and was distressed at night, learning of their attention. Unknown to her, however, that the pair already added bromide to Emily's regular sleeping medicine, which contained strychnine. The bromide made the dose of sleeping powder lethal, killing Emily later.
After the murder, inside Emily's room, Alfred discovered the letter between him and Evelyn, and attempted to steal it but was failed due to Poirot and Hastings apporaching the room. As such, he hid the letter and decided to take it back once John was traled.
Soon, Alfred intentionally had himself into the custody in order to throw away suspicions, while Evelyn prepared to frame John for the crime. However, his intention of hiding the letter between him and Evelyn failed after Poirot discovered the said letter after a remark from Hastings, solving the case.