Christiane Amanpour talks to director Alex Gibney about his documentary 'Mea maxima culpa - Silence in the house of god', about how the cover-up for the sex abuse scandal can be traced to the top of the Vatican. Cardinal Ratzinger (later pope Benedict) received pleas, including from an arch bishop, to de-frock father Lawrence Murphy, a man who may have abused as many as 200 deaf boys at St John's school for the deaf in Wisconsin. Yet nothing happened.