Infiltration of Nazi support and escape organisations (the most famous one being the ODESSA network and its various "ratlines") and those believed to be aiding and abetting them. However, many suspected war criminals were also given amnesty, and some reached high positions in post-war administrations (e.g. Maurice Papon, who became Police Prefect of Paris in charge during the Algerian War (1954–62); he was blamed for the 1961 Paris massacre). Others were never even tried such as Robert de Foy who resumed being head of the Belgian State Security Service 1945-1958.