In the course of investigative and later judicial proceedings, first the Allied, then also the Italian and finally, from the 1960s onwards, the judicial authorities of the Federal Republic of Germany collected and compiled a wealth of documents on war crimes in occupied Italy. These documents can be viewed today in archives in the United States, Great Britain, Germany and Italy.

With regard to this material, some source-critical notes are necessary: for example, it should be noted that such files are usually early statements of the facts. Consulting additional sources is a requirement for verification. Only the results of completed trials can be considered conclusive. But even here, historiographical research continues afterwards: The discovery of new documents can result in additions, new elements of evaluation or even changes to the trial results.

An important part of the judicial material was collected by the Zentrale Stelle (ZSL, Central Office of the Land Judicial Authorities for Investigation of National Socialist Crimes) in Ludwigsburg near Stuttgart. Founded at the end of 1958, the Central Office initiated more than 7250 preliminary investigation proceedings and investigated many thousands of Germans. With the transfer of the records to a local branch of the Federal Archives as of 1 January 2000, this institution also offers good working conditions for historians.

The holdings here contain a wealth of material of interest for the investigation of the massacres in Italy. The Central Office has opened dozens of investigations in this field, which were then handed over to the competent judicial authorities. The most recent cases concern the massacres of Sant'Anna di Stazzema, Monte Sole, Vallucciole and Civitella, which were initiated after 2000. The material collected by the German investigators, in particular the transcripts of the interrogations of witnesses and suspects, allow new insights into the course of these acts of violence.