Lev Romanovich Sheinin (1906–1967) was a Soviet writer, journalist, and NKVD investigator. He was Andrei Vyshinsky's chief investigator during the show trials of the 1930s, and a member of the Soviet team at the Nuremberg trials. In the 1930s he collaborated with psychologist Alexander Luria in researching the emotional reactions of suspected criminals, work that contributed to the development of polygraph testing. In 1951 he was arrested on suspicion of spying, one of the arrests associated with the Doctors' plot.