Sonia Faleiro’s gripping, real-life murder mystery begins as an Indian villager — a farmer with a side job as a teacher — disapprovingly spies two teenage girls talking on a mobile phone in the fields. Determined to do his duty in a community where “a girl’s life was everyone’s business”, he relays what he has seen to their older male relative.

For India’s political leaders, rising use of mobile phones is a proud symbol of modernisation and economic progress. Not so for residents of the deeply conservative villages in the impoverished north of the country.

In Katra Sadatganj, Uttar Pradesh — the setting of this compelling whodunnit — mobile phones pose a threat to the traditional social order, in which young girls are tightly controlled until married off by their parents.

“A phone was a key to a door that led outside the village via calls and messaging apps,” Faleiro says. “The villagers were afraid of what would happen if women stepped through this door. They might get ideas such as whom to marry.”

The teenagers of this story — referred to in the book by the pseudonyms Padma and Lalli — are first cousins and inseparable best friends who scribble poetry, secretly wear lipstick and dream to “be something”. But they fall under suspicion and surveillance as they engage in covert meetings with a boy from a neighbouring village. Weeks later, the girls, aged 16 and 14, are found dead, hanging together by their own colourful dupattas from a mango tree.

The deaths, in May 2014, made national headlines in India, where the girls were quickly presumed to have been raped and murdered by higher-caste men — a grim example of the pervasive sexual violence against vulnerable women.

That, at least, was the claim of the victims’ families, who refused to let the bodies be brought down from the tree for nearly 12 hours, as they instead demanded justice and accused their higher-caste neighbours, and local police officers, of murder.

Faleiro, the India-born, London-based author of an acclaimed book about the women of Bombay’s gritty dance bars, intended to use the crime as the heart of a planned book on rape in India.

But as she pored over official records and interviewed more than 100 people — including the girls’ relatives, the accused, and criminal investigators — Faleiro discovered a complicated, tragic story about different forms of repression of Indian women, even in their own homes.

Taut with dramatic tension, The Good Girls vividly captures the sights, sounds, smells, preoccupations and oppressiveness of the village. This is a claustrophobic world in which even visiting the local bazaar is deemed inappropriate for unmarried girls. Tending to livestock, or relieving themselves in the fields, is the only legitimate escape from their own four walls and domestic drudgery.

When the teenage protagonists are finally allowed a trip to the fair — mainly to humour a cousin visiting from the city — they are warned not to eat or drink anything: “It wouldn’t do for girls to be seen enjoying themselves in a public place.”

The night they go missing, their male relatives mount a frantic yet silent search to avoid alerting neighbours to an event that could affect the girls’ marital prospects — or their family’s honour.

“In less than an hour since they were gone . . . who they were and what had happened to them was already less important than what their disappearance meant to the status of the people left behind,” Faleiro writes.

The book paints a damning picture of non-existent police investigative capacity, which underpins India’s notoriously low criminal conviction rate, and an official impulse to “settle matters” — that is, bury them — rather than hold people to account.

The book also effectively captures the circus-like atmosphere that typically follows heinous crimes in India, where television media trials and political grandstanding replace the painstaking police work required to prepare for a criminal trial.

In this case, as the families are caught up in the maelstrom of the teenagers’ deaths, Faleiro writes sensitively about her subjects’ actions and motivations, while the investigation reaches its final devastating revelation.

The tragedy in Katra was hardly unusual. It was, as the title suggests, an ordinary killing, reflecting pervasive tensions in Indian villages between ideals of family honour and new aspirations for individual freedom. In this clash, young women are paying the highest price.

The Good Girls: An Ordinary Killing by Sonia Faleiro, Bloomsbury Circus, RRP£16.99, 352 pages

Amy Kazmin is the FT’s South Asia bureau chief

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