Berlin- Eleven former prisoners of the US armed forces on Tuesday filed a lawsuit in Germany calling for outgoing US Secretary of Defense Donald Rumsfeld and other American officials to be investigated for war crimes. Backed by human rights groups, the 11 ex-prisoners say they were tortured at Iraq's Abu Ghraib prison and the US prison at Guantanamo Bay in Cuba on the orders of Rumsfeld and other top members of US President George W Bush's government.