A decision to investigate 30 alleged former guards at Auschwitz was prompted by the case of Ukraine-born John Demjanjuk.
Demjanjuk was the first Nazi war criminal to be convicted in Germany without evidence of a specific crime or victim but purely on the grounds he had served as death camp guard.
He died last year, aged 91, while appealing against a five-year jail sentence for complicity in the murder of more than 28,000 Jews at the Sobibor camp in Poland.
More top news
Merrill Lynch has been fined £34.5 million for failing to report 68.5 million transactions, the Financial Conduct Authority has said.
Most people back a change in the law to ban unpaid internships that last for more than four weeks, a new poll suggests.
The favourites to win the Venice marathon finished behind a local runner - after they were led along the wrong route by a motorcycle guide.