According to the news outlet, the investigation focused on Nazi soldiers who served in German concentration camps where about 5.7 million of Soviet soldiers were detained, 3.3 million of whom died in captivity.
"Our archives contain data on roughly 250 camps with the information about the guards who served there", head of the office Thomas Will said as quoted by the Welt am Sonntag.
According to Will, the office has already identified about 2,000 guards responsible for the deaths of the Soviet soldiers, and some of the Nazis who are responsible for the deaths of Soviet war prisoners may be still alive.
The number of investigations against Nazi war criminals significantly increased after 2011 when Munich's court sentenced Ukrainian-born John Demjanjuk, who served as a guard at Sobibor extermination camp, to 5-year imprisonment over the accessory to the murder of over 28,000 Jews. However, in 2012, Demjanjuk died at the age of 91, and the sentence did not come into effect.