The Nazi-hunting Simon Wiesenthal Center said Monday it had gleaned dozens of helpful tips from a poster campaign in Germany seeking information on the last living perpetrators of the Holocaust.
As he announced an expansion of the campaign to more German cities, its initiator, Efraim Zuroff, said four cases involving Nazi suspects in their 80s had been handed to state prosecutors for investigation based on information from the public since July.
Zuroff said the suspects included a Waffen-SS officer allegedly involved in a 1944 massacre in France, a woman who had served as a guard at several concentration camps including Auschwitz, and a man who had worked at Dachau outside Munich.
He said prosecutors were expected to decide in December whether to pursue the criminal charges.
The Center said it received tips on 110 suspects, 81 of whom live in Germany while the others lived in the United States, Mexico, Spain and another 13 countries.
Zuroff called the initiative "an overwhelming success", saying it had only received "about two dozen" emails that were critical of the campaign.
"I have to say that the results that were achieved in the first round were very surprising for us," Zuroff told reporters.
"This also sends an important message to the families of the victims on the road to justice."
In July, the Center hung posters on the streets of three major German cities asking for tips from the public on elderly Nazi war criminals still at large. In the coming weeks, another eight cities are to be included.
Part of the Center's "Operation Last Chance" to catch the surviving suspects behind World War II-era atrocities, the signs offer a reward of up to 25,000 euros ($34,000) for information leading to the capture and conviction of such criminals.
Germany has launched a raft of new criminal probes this year based on a precedent set by the conviction in May 2011 of former death camp guard John Demjanjuk.
A Munich court sentenced the Ukrainian-born Demjanjuk to five years' imprisonment for helping the Nazis kill almost 30,000 Jews during his time at the Sobibor extermination camp in German-occupied Poland during World War II.
In a legal first, it found that simply demonstrating Demjanjuk's employment at the camp, rather than his involvement in specific murders, was enough to implicate him in the killings committed there.
The federal office investigating Nazi war crimes in September passed on a list of 30 suspects believed to have worked at Auschwitz to regional prosecutors with recommendations to bring charges.