In the novella Murder in the Mews, Major Eustace was an acquaintance of Barbara Allen. He had known her while she was in India and had learnt some unpleasant facts about her which he used to blackmail her on her return to England, with ultimately fatal results. Witnesses saw Eustace leave Barbara's house at ten-twenty on Guy Fawkes night. He was thus the last person known to have seen her before she died and thus a suspect. A piece of broken cuff link belonging to him was also found on the floor near the body.
Eustace was described as a military-looking gentleman about forty-five with a toothbrush moustache. On that night he was wearing a dark blue overcoat and bowler hat. He drove a Standard Swallow saloon and had a serviced flat on the Cromwell Road.
Both Barbara's fiance M. P. Charles Laverton-West and her friend and housemate Jane Plenderleith disliked Eustace. She considered him a little "hairy at the heel" and "not out of the top drawer".
At the time of Barbara's death, Major Eustace was already known to the police. According to Japp, Eustace used two or three different aliases, he had a "tricky business over a cheque" and a "nice affair" when he stayed at the Ritz under the name of "Colonel de Bathe". He had also swindled half a dozen Piccadilly tradesmen.
Portrayals[]
Major Eustace was played by James Faulkner in the film adaptation of the story which was episode 2 of series 1 of ITV's Agatha Christie's Poirot drama series. In the original story, he claimed to have gone to "Far East Club" after leaving Barbara. In the adaptation, Japp and Inspector Jameson actually interview him at a club. The club is not named but had waitresses and a singer dressed in Far East costumes. Eustace was apparently manager of the club and was shown handing the keys of the liquor storage to a waiter.
In the adaptation, Japp addresses Eustace as "Robert Erskine Eustace" when arresting him. These first names are not found in the original story.