Born in Arizona, Jahn spent much of his youth moving between his father's apartment in Austin, Texas, and his mother's various rentals in and around Los Angeles, California.

His first novel, Acts of Violence, takes place over a period of three hours and revolves around the murder of Katrina Marino, a bar manager stabbed in the courtyard outside her apartment block.

Though inspired by the murder of Catherine Genovese, the case that first spurred research into the diffusion of responsibility, Jahn has said he wasn't interested in writing a didactic work.

It was inspired, in part, by the kidnapping of Jaycee Lee Dugard, though the details of the novel bear no relation to the facts of the case, with characters, events and locations being entirely fictional.

It concerns the kidnapping of a seven-year-old girl and her father's attempts to rescue her, when, seven years later, months after she has been declared dead, he learns that she is still alive.