The spectre of true crime was stalking the aisles at this year’s London book fair, with publishers snapping up investigations into past evils in the wake of successes in podcasting and television such as Dirty John, Serial and The Teacher’s Pet.

Offers were flying in for former Waterstones bookseller Susan Jonusas’s first book Hell’s Half-Acre, a study of the the Bender family of serial killers in Kansas in 1873. Jonusas, 24, left Waterstones in December to write full-time. “Buried on a homestead seven miles south of the town were 11 bodies in varying states of decay. Further investigation revealed a well containing remains of even more victims. The number of people murdered was estimated at 20,” said Jonusas’s literary agency. “The idea that a family of seemingly respectable homesteaders were capable of operating ‘a human slaughter pen’ appalled and fascinated the nation. But who the Benders really were, why they committed such a vicious killing spree and what became of them when they fled from the law is a mystery that has remained unsolved to this day.” UK rights are still being finalised, with Viking snapping it up for a six-figure deal in the US. Agent Georgina Capel, who was fielding offers for the book, said: “I suspect the true-crime podcast thing is driving the current interest.”

Foreign publishers were also eyeing mortuary technician Carla Valentine’s Murder Isn’t Easy, which sold to Little, Brown UK earlier this spring. This sees Valentine applying her knowledge of modern forensic science to the murders in Agatha Christie’s mysteries. “The basic tenet of forensic science is that ‘every contact leaves a trace’, and Carla begins her study into Christie’s novels as any investigator would – by surveying ‘the scene of the crime’ (a phrase coined by Christie herself),” said literary agent Martin Redfern at Northbank Talent Management. “She examines the use of fingerprints, firearms, handwriting, impressions, blood-spatter analysis and toxicology in the novels, before finally revealing the role the dead body itself played in offering vital clues to dastardly crimes.”

Redfern said there was considerable interest in true crime from publishers, “both historical and present day, focusing not just on criminals but all those involved in the criminal justice system, from barristers to psychologists to prison officers”.

And a 13-publisher auction for forensic psychiatrist and psychotherapist Dr Gwen Adshead’s investigation into the nature of evil, The Devil You Know, was won by Faber. Co-written with Eileen Horne, the book is a series of case studies of the patients Adshead worked with over 20 years at Broadmoor hospital. Faber’s Laura Hassan said the book “has the power to explode our assumptions and ultimately to change our minds, whether about the nature of evil, society’s attitude towards punishment or the possibility of rehabilitation”.

Jonny Geller of agency Curtis Brown said the mood at the fair was positive and while no one was talking about Brexit, it was the elephant in the room.

“With Brexit, Trump and what is happening in Brazil, there is so much turbulence in markets that politics does impact what people will be reading,” he said. “What I saw from the Americans was that they were finding literary fiction difficult. They have become introverted in their reading, turning to buying stacks of self-help, psychology, diet books. In that environment, fiction can sometimes suffer. I wonder if Brexit will make people want to read more out of themselves, and lead to a surge in fiction.”

The holy grail of the fair was narrative non-fiction, including true crime, Geller said: “People want real, authentic experience, and written well. Look at Adam Kay’s This Is Going to Hurt, which has spent 42 weeks in the bestseller charts … the interest in true crime is the natural progression for readers tired of thrillers, who still want suspense and that expert voice.”

There was also room at the fair for news of more established names: a new novel from Salman Rushdie, Quichotte, inspired by Don Quixote and following the adventures of an ageing travelling salesman who falls in love with a TV star and travels across the US to prove himself worthy of her hand; a sequel to PS I Love You from bestselling Irish novelist Cecelia Ahern, which revisits the world of Holly seven years after her husband’s death; and “a no holds barred” memoir by Elton John, written with Guardian critic Alexis Petridis.