Amanda Jayatissa has won praise for her compelling thrillers. Her third novel, Island Witch, showcases a true appreciation of the horror genre: a tale of witchcraft and demon-priests in 19th-century Sri Lanka, it’s every bit the gothic nail-biter. Influenced by supernatural classics such as Steven King’s Carrie, Amanda talks to Chanchala Gunawardana about dark forces, feminism and folklore with a devilish flavour.