The task of the Central Office is to collect, to scrutinise and to evaluate the entire accessible material on Nazi crimes in Germany and abroad. Its main aim is searching for acts limited in space, time and committed by a certain group of culprits and to determine which persons involved into these atrocities can be still prosecuted. As soon as the Central Office has found the group of the perpetrators who are to be prosecuted, the preliminary investigations are closed and the files are transferred to this prosecutor’s office in charge. The latter is obliged to process the whole case. Here, the Central Office renders investigative assistance further on. This method enables the public prosecutor’s offices not only to conduct investigations in every single case (as it had been until 1958) but from that point onward, to handle the case, divided into component complexes, profoundly and systematically as a whole.