Katrina Rieger

In the short story How Does Your Garden Grow?, Katrina Rieger was the Russian companion of Amelia Barrowby. Amelia's niece Mary Delafontaine murdered her aunt when she learnt that her aunt had suspected that she and her husband had been embezzling her funds. Mary was also aware that Amelia had willed most of her wealth to Katrina and so framed her for the murder. As Katrina administered Amelia's medications, this was easily done where the murder was done by poison. Katrina was arrested for the murder but as Poirot would say, she had at least one friend, him.

Portrayals
Katrina is played by Catherine Russell in the film adaptation of How Does Your Garden Grow? in Series 3 of ITV's Agatha Christie's Poirot. Here her name is spelled "Reiger" although the original story gives it as "Rieger". Her role in the adaptation is considerably enhanced. She is seen engaged in secret meetings with Nicholai, a member of the Soviet embassy, giving some credence to the rantings of Henry Delafontaine about Katrina being a "red" or a "bolshie". Poirot discovered however that this was not credible. She kept a picture of the tsar on her dresser and was deeply religious. She later told Poirot that her real name was "Regimirov" and she was, as Poirot had earlier guessed, she was a Russian emigre aristocrat. She was having a secret romance with Nikolai, something which would have been illegal for him, being a communist functionary. In the adaptation, she was not arrested but sought sanctuary in the Russian church in London until Poirot convinced her to give herself up voluntarily while he worked to exonerate her.