The death of Sheku Bayoh following his arrest in Fife three years ago remains one of the most controversial moments in Police Scotland's short history. Following the decision not to prosecute the officers who restrained him, Mr Bayoh's family claim there has been a cover-up, and say they have been denied justice. Mark Daly investigates the circumstances surrounding the death, using previously unseen material. The film poses fresh questions about the police response and asks if racism could have played a part.