Christy Mangan knows how hard it is to solve a murder. In his forty-year career, Mangan participated in or led over 100 murder investigations. And he set up the Garda cold case unit to examine some of the state's most troubling unsolved killings. Now, in Cracking the Case, he takes a deep dive into how investigations are run. Cracking the Case includes, among others, the investigation into the 1985 death of Fr Niall Molloy and the extraordinary story of Charlotte and Linda Mulhall - dubbed 'the Scissor Sisters' - who killed and dismembered their mother's abusive boyfriend.