Sergey Prokudin-Gorsky
Sergey Mikhaylovich Prokudin-Gorsky (, ;  – September 27, 1944) was a Russian chemist and photographer. He is best known for his pioneering work in colour photography and his effort to document early 20th-century Russia.
Abram Slutsky
There are two unofficial accounts of Slutsky's death. The first appeared in Orlov's "Secret History of Stalin's Crimes" (1953) and presumably is based on gossip Orlov heard in France or Spain in 1938. In Orlov's version, Slutsky was invited to a meeting in the office of Mikhail Frinovsky, head of the GUGB, in the Lubyanka. Shortly afterward, his deputy, Sergei Shpigelglas, was called into the office and he observed Slutsky slumped in a chair with tea and cakes at the table beside him. Frinovsky said Slutsky had died suddenly of a heart attack. The chief of the NKVD, Nikolai Yezhov, ordered Slutsky's body put in the main hall of the NKVD club and surrounded by an honor guard of NKVD officers. However, the embalmers neglected to cover the tell-tale spots on Slutsky's face which indicated to the mourners that he had been poisoned with hydrocyanic acid.