Despite active opposition from Russian authorities, Russian historian Nikita Pyetron has published pictures showing for the first time in history, the faces of 11 of the 125 Russian NKVD officers who murdered Polish POWs at Katyn in 1940. The identity of the murderers has been unknown for 68 years because they had been hiding the truth even from their own families. Some have lived to an age old enough to be interrogated as part of the Katyn investigations of the past decade but Russian prosecutors sealed the depositions.
Sorry about the quality of the pics, Poland's TVP1 channel has a streaming video showing more images but it is not available to people outside of EU.
Of the Russian henchmen present at Katyn, the most notorious was an NKVD officer Vasili Blokhin. He personally executed 50,000 people throughout his 30 year long career, including an unknown number of the Polish officers. All of the 50,000 victims were killed with a single shot to the back of the head. For his efforts, Blokhin was promoted to the rank of a general.
According to the historian Pyetron, Russia is still trying to hide the scale of the mass repressions in the 1930s and 1940s in an attempt to present the history of Russia in a more favorable light.