Colonel Race is a recurring character in Agatha Christie novels, who previously helped Poirot solve a case in
Cards on the Table. Though he is not as well-known as Poirot, he is the lead detective in other books. His appearance here, halfway through the journey, marks a turning point in the story. The fact that he is looking for a murderous political agitator is also significant, as Richetti and Ferguson have shown an interest in radical politics.