Norma is lured from Dr Stillingfleet by an ad in the newspaper to meet David, and is again drugged. Frances kills David. She sets it up to appear that Norma did it, but the blood on the knife was congealed when Norma found herself holding it. With police and family gathered in the flat, Poirot announces that Andrew did die in Africa. Robert Orwell is posing as her father to gain the wealth of the family. He had David paint portraits of him and his late wife in the style of a painter popular 20 years earlier as part of the ruse. Most cruelly, he and his wife have been giving Norma various drugs that give her hallucinations and an altered sense of time, to set her up as guilty. Further, the wife had poisoned herself hoping to pin that on Norma, too. Louise wrote to Andrew on learning he was back in England, so Frances killed Louise; this is the murder Norma feared she did. The woman posing as her stepmother was also Frances, who used a blonde wig to cover her dark hair when changing roles. Poirot takes the wig from her bag to make that point. Murder of the two who could expose the imposters was just one of her crimes. Sonia is exonerated when she finds the papers Sir Roderick misplaced, and the two will marry. Poirot had chosen Dr Stillingfleet to help him with Norma in hopes the two would marry, and they will.