Mark Isaevich Gai (Russian: Марк Исаевич Гай) (real name: Mark Isaacovich Shtoklyand; Марк Исаакович Штоклянд) (30 December 1898 – 20 June 1937) was a Soviet security and police officer, who played a major part in preparing the Great Purge, during the early stages of which he was arrested and executed.
He joined the Red Guards around the time of the Bolshevik Revolution, and operated underground in Kiev during the early part of the Russian Civil War.
[1] He joined the Cheka in Ukraine in May 1920, and transferred in May 1922 to Moscow, where he held a succession of posts, rising to be deputy head of the Economic Department of the OGPU in August 1931.
[4] During the preparations for the first of the Moscow Show Trials, when the former Trotskyist Ivan Smirnov was refusing to confess, Gai arranged a confrontation with the prisoner's former wife, who urged him to co-operate, not knowing that he would be executed.
[5] In July 1936, he was involved, with his assistant Zinovy Ushakov, in the arrest, interrogation and torture of Commander Dmitry Shmidt, who was forced to give incriminating testimony against Marshal Tukhachevsky and other senior officers, in what became a major purge of the Red Army.