Presenter Rageh Omaar describes his ordeal in Yemen last May when-together with two BBC colleagues - he spent two weeks in captivity after being arrested by Yemeni authorities. Sue Lloyd-Roberts talks to the Dalai Lama , Tibet's spiritual leader, as she reports on a fresh waveof religious persecution facing Tibetans. And Olenka Freinkel reports on the wartime murder of 15,000 Polish army officers by Soviet secret police - a crime denied for 50 years.