The Edge of Darkness by Vaseem Khan

India, 1951. After wilfully ignoring orders from her superiors, Persis Wadia, India's first female police detective, has been exiled from Bombay to the wild and mountainous state of Nagaland. As India's first post-Independence election looms, and tensions rise across the country, Persis finds herself banished to the Victoria Hotel, a crumbling colonial-era relic, her career in ruins.

But when a prominent local politician is murdered in his locked room at the Victoria Hotel, his head missing - a case appears quite literally on her doorstep. As the political situation threatens to explode into all-out havoc, Persis has only days to stop a killer operating at the very edge of darkness...

The sixth rip-roaring thriller in the award-winning Malabar House novels and a perfect entry point to the series.