One significant aspect of the development of detective fiction in Spain in the latter part of the twentieth-century is its emergence as a political genre. The modern Spanish detective novel, and the urban thriller or novela negra in particular, has been used by Spanish writers, both during the Franco regime and since, as a vehicle for social observation and cultural criticism, to voice dissent and disagreement with the prevailing political ideology.

The new Spanish novela negra often subverts the traditional detective story, with its firmly roots in the idea of preserving bourgeois legal and social order and punishing transgression. Detective fiction is traditionally teleological, ending in the triumph of reason and stability and the reinstatement of narrative and social order. On the other hand, the novela negra tends to offer a destabilizing view of crime in society, exposing and criticizing repression, punishment, and social control, and focusing instead on the underlying social and political causes of crime. Rather than celebrating the reimposition of the status quo, as the traditional detective novel does, the novela negra questions the rationality of the prevailing social order, of the justice meted out by courts, and of the ethics of the police force, offering instead a moral critique of the shortcomings of ordered, capitalist society.

From timid beginnings in the 1950s and ‘60s, detective fiction grew in confidence during the last years of the Franco regime, and began to explore social issues and shifting moral values, as well as memories of the Civil War, questioning the status quo, investigating political and economic power, and offering a more or less camouflaged political allegory or indictment of the Franco dictatorship. Contrary to the traditional Marxist view of the alienating effect of detective novels and other forms of popular fiction which reinforce conservative cultural values, the new detective story resorted in Gramscian fashion to taking a popular cultural genre and infusing it with a with a heterodox message. The detective novel offered an opportunity for the writer to present a veiled critique of the dictatorship, affording oblique glimpses of economic injustice, social inequality, the lack of freedom and human rights, economic corruption, and the repressive police and legal system of the dictatorship.

The earliest sign of this trend can be seen in El inocente (1953), a highly literary story by Mario Lacruz often considered the first Spanish novela negra.