The German justice agency which leads investigations into Nazi war crimes says the cases of all former guards at the Auschwitz death camp are to be re-examined.
Six million Jews were murdered in the Holocaust, with around 1.1 million killed in Auschwitz alone.
According to the agency in the town of Ludwigsburg, 40 former Auschwitz guards were still alive despite their old age. 30 of this number remain in Germany and could therefore face trial by a German court.
German media has reported that the oldest of the former guards was born in 1916 making him around 97 years old with the youngest born in 1926 making him around 87.
The nature of investigations has shifted in recent months with officials keen to shine a spotlight at anyone who worked at the Nazi death camps.
Chief Prosecutor Kurt Schirm said, "The accused ... are all former guards at the concentration camps Auschwitz-Birkenau and we take the view that this job - regardless of what they can be individually accused of - makes them guilty of complicity in murder."
The Ludwigsburg agency has said that it will hand over its findings to officials in 11 German states to decide whether to bring charges against the 30 former guards.
In addition the agency also said that all former employees of death camps and special killing squads (Einsatzgruppen) would also face scrutiny.
The senior ages of those involved looks to be speeding up the prosecution process in Germany. On Monday,(September 2) 92-year-old Siert Bruins, went on trial in the western German town of Hagen on charges of having shot in the back and killed a Dutch resistance fighter in 1945.