"We started off with 49 lawsuits, but some of the people live abroad and at least nine of the accused have passed away," said Kurt Schrimm of Germany's Central Office of the State Justice Administrations for the Investigation of National Socialist Crimes.

The accused are people who worked as guards in the Auschwitz-Birkenau concentration camps thereby contributing to the murder of millions of people by the Nazi regime. Prosecutors must now act very quickly if they hope to bring any of the 30 remaining defendants in Germany to justice, as they are all between 87 and 97 years of age.

"I'm convinced that the prosecutors are aiming to wrap up the proceedings as quickly as possible, but it will still take several months," said Schrimm.

Poster campaign to find suspects

Efraim Zuroff, head of the Simon Wiesenthal Center in Jerusalem, an organization fighting anti-Semitism and promoting human rights, supports the measures. "What we're hoping is that these cases will be treated with urgency, so that these people can be brought to justice before they die," Zuroff told DW.

The Simon Wiesenthal Center has gathered evidence pointing to 111 potential suspects through the "Late, but not too late" poster campaign that ran in Berlin, Hamburg and Cologne in recent months. The list included at least four people that fit the legal criteria for being charged with a crime.

According to various media, the central office for Nazi crimes has already launched an investigation into two of these cases. But according to Schrimm, neither he nor his deputy has heard anything of this. Meanwhile, the Simon Wiesenthal Center is continuing its poster campaign, extending it to the cities of Munich, Leipzig, Stuttgart, Magdeburg, Rostock, Dresden, Nuremberg and Frankfurt.

Schrimm's office, however, is basing its current investigations on a list of 5,000 names of people who worked as overseers in the Auschwitz concentration camp. "The list has existed for decades and nobody really knows who put it together," said Schrimm. "There is some indication, however, that it was created in the 1960s by the Hesse judiciary or police." Thirty of these cases are current candidates for further investigation.

Proceedings against former concentration camp guards have proven difficult in the past. In 1969, Germany's Federal Court of Justice stipulated that, in the case of Auschwitz, individual responsibility for a crime needed to be proven - in other words, simply being part of the mass-murder in general was not enough reason to stand trial. This kind of evidence was already difficult to attain back then - today it is even harder. Written sources are rare and many witnesses have passed away.

New legal possibilities - and challenges

A turning point came in 2011, when a Munich court sentenced John Demjanjuk, a former guard at the Sobibor extermination camp, to five years in jail after finding him guilty of over 20,000 counts of being an accessory to murder. No individual guilt needed to be proven in his case - his former job as guard at Sobibor sufficed. "This case changed the legal situation," commented Zuroff, adding that the "Late, but not too late" poster campaign would not have been possible otherwise.

Demjanjuk appealed against the verdict at the Federal Court of Justice, but passed away before the proceedings were reopened. "We don't know what this court would have decided," said Schrimm.

A major legal obstacle in the case of Auschwitz is that not all of it was a death camp: it encompassed a concentration as well as an extermination section. And while many prisoners were murdered in gas chambers on arrival, those in the concentration camp had a small chance of survival. Demjanjuk worked in a straightforward extermination camp, but the contribution to murder is harder to prove in the case of Auschwitz guards.

It is still not certain whether the 30 alleged Nazi criminals in question can be brought to trial. Some also wonder if Germany even has jurisdiction, since for this to be the case, either the suspect must be a German citizen, at least one of the victims must be a German citizen, or the crime must have been committed on German territory. If none of these criteria apply, the trial must take place abroad - but considering the age of the 30 Auschwitz suspects, this may not be feasible from a time perspective.

Schrimm and his team at the Central Office still have a lot to do. "Until now we've only been looking at Auschwitz, because of that list," he said. "Unfortunately, there isn't a list like that for other concentration camps, such as Treblinka and Sobibor. It's going to be a big job, but it's doable. We will also have another look at all the concentration camp documents that we have in our archives."