REUTERS/Caren Firouz Prime Minister Nawaz Sharif appeared before a panel investigating his family's wealth on Thursday, the first time a Pakistani prime minister has been grilled by an investigative agency. The scrutiny of Sharif has gripped Pakistan, but the investigation - ordered by the Supreme Court - has become increasingly politicised. Sharif arrived at the Joint Investigation Team (JIT) in Islamabad clad in traditional shalwar kameez tunic and baggy trousers, but did not speak to...