In "The Big Four", Agatha Christie gave him a mysterious "twin brother" named Achille
In 
The Big Four ( 1927), for example, he claimed to have a twin brother, Achille, and 
later... [DOC] [TLE] Agatha Christie - by Michael E. Grost [PAR] Agatha Christie: Career | Partners in Crime | Impossible Crimes .... Middle East, 
Max Mallowan, and lived with him for many years in Baghdad, Iraq, as well as ...