Knot in the gut

The plot of the novel is surreal.
Paul, a small-time crook, falls in love with an unusual girl, Jeanne, who introduces him to the high-stakes world of armed robbery, only to betray him with another man.
Following the betrayal, Paul begins living in a hallucinatory state, constantly dreaming of a little man with a mustache.
During a bank heist, he believes he sees this figure in one of the clerks and, to free himself from the nightmare, kills him.
A police pursuit ensues, during which Paul begins a "descent" into the underworld: both physically and spiritually.
Paul loses control of his life and lapses into a paranoid state.
In this condition, he murders a woman who had taken him into her home and shielded him from the police.
The book chronicles the decline of an individual and his transition from a precarious equilibrium to a neurotic and self-destructive condition.
In this sense, it stands as the representation of a broader situation, one that could happen to anyone; yet the author develops it in a paradoxical and inexplicable manner, leaving the reader bewildered and disappointed by the superficiality of the narrative.