Motifs are recurring structures, contrasts, and literary devices that can help to develop and inform the text's major themes.

Detection 

The process of investigating the Osage murders is a core plot element, but detection is also a motif across the book. Grann incorporates historical details about the history of law enforcement, the role of private detectives, and different techniques used by the police (handwriting analysis, finger printing, and other practices associated with Bertillonage) as crucial elements of his narrative reconstruction of the past. He notes, too, that history itself is akin to a detective, sure of the facts and overly confident, flaws that do not prevent it from delivering justice. As a reporter, he, too, is a kind of detective, as evidenced in book’s third when Grann enters the narrative by proposing answers for some of the unresolved killings. Across all the different ways that detection work, however, one thing remains constant. Detection needs to recognize its ethical dimension if it wants to avoid the danger of being unwarranted intrusion into the private lives and secrets of people, as the exposure of Mollie’s youthful marriage to Henry Roan demonstrates. 

Repetition 

Although every work of literature uses repetition as part of its composition, Killers of the Flower Moon repeats and retells stories from the Reign of Terror in multiple ways, a structure that fully immerses readers in the events. Multiple theories are floated, investigated, and then discounted for the murder of Anna Brown, for example, which leaves the reader as confused and unsure as the people themselves. Thematic concerns in the book thus become integral to its interpretation, a destabilization that is enhanced as perceptions of people’s true characters alter. Because so few people tell the whole truth in any given situation, the regular repetition of events tends to make things murkier, rather than clearer. The stories are passed down through the generations among the Osage, as descendants seek to clarify what actually happened to their ancestors. Grann notes that the stories have been told in newspapers, in dance, in film, in poetry, on radio, and in book (both fiction and history). They are buried in the National Archives where they might be read differently, and buried in the grave, never to be told again. Grann’s use of repetition stresses both the importance of telling stories over and over, so they won’t be forgotten. He also emphasizes that repetition might make it the real story harder to find or follow. 

Prejudice 

There are various forms of prejudice that help organize this book, and the most important is racism. White characters regularly discount the capacity, and even the humanity, of Native American characters, a tendency that dating back to the nation’s foundation. Prejudice complicates justice and shapes national legends, such as in the myth of the Wild West, which is predicated on glorifying the routine slaughter of “savages.” It also informs ideas about wealth and propriety, in that it determines what it means to use things, including money, properly, as well as assumptions about cultural norms. But racism is not the only form of prejudice in the book. Unfavorable comparisons are made between professional agents and the rougher lawmen who operate on the frontier. Not only is there class discrimination in this difference, but it also relies on prejudicial views of urban and rural ways of life. Gender discrimination also plays a role, as women are granted even fewer rights and privileges than men.