The drama is based on the memoirs of the London detective DCI Colin Sutton, who led the investigation into the murder of Amélie Delagrange during the 2000s.
In August 2004, Amélie Delagrange, a 22-year-old French student who was visiting the UK, was found dead on Twickenham Green with head injuries after a brutal attack with a blunt object.
Over the three-part series we follow DCI Colin Sutton, who has little previous experience of murder investigations, as he tries to solve the case. Sutton painstakingly and carefully connects the dots as he attempts to track down the serial killer Levi Bellfield.
Katie plays DS Jo Brunt
Watch on Sunday 6th January on ITV at 9pm.