Operation "Trest"/"Trust" - by KGB (Soviet Union), the Committee for State Security, Komitet Gosudarstvennoy Bezopasnosti.
Operation Trust (операция "Трест") was a counterintelligence operation of the State Political Directorate (OGPU) of the Soviet Union. The operation, which ran from 1921-1926, set up a fake anti-Bolshevik underground organization, "Monarchist Union of Central Russia", MUCR (Монархическое объединение Центральной России, МОЦР), in order to help the OGPU identify real monarchists and anti-Bolsheviks.
The head of the MUCR was Alexander Yakushev (Александр Александрович Якушев), a former bureaucrat of Ministry of Communications of Imperial Russia, who after the Russian Revolution joined the Narkomat of External Trade (Наркомат внешней торговли), when the Soviets had to allow the former specialists (called "specs", "спецы") to take positions of their expertise. This position allowed him to travel abroad and contact Russian emigrants.
MUCR kept the monarchist general Alexander Kutepov (Александр Кутепов), head of a major emigrant force, Russian All-Military Union ( Русский общевоинский союз), from active actions, who was convinced to wait for the development of the internal anti-Bolshevik forces.
Among the successes of Trust was the luring of Boris Savinkov and Sidney Reilly into the Soviet Union to be arrested and executed.
Some modern researchers say that there are reasons to believe that both persons had doubts in MUCR, and they went illegally into the Soviet Union for their own reasons, using MUCR as a pretext.
The Soviets did not organize Trust from scratch. The White Army had left agents behind who were sleepers and there were also Royalist Russians who did not leave after the Civil War. These people cooperated to the point of having a loose organizational structure. When the OGPU discovered them, they did not liquidate them, but expanded the organization for their own use.
Still another episode of the operation was an "illegal" trip (in fact, monitored by OGPU) of a notable emigree Vasily Shulgin into the Soviet Union. After his return he published a book "Three Capitals" with his impressions. In the book he wrote, in part, that contrary his expectations, Russia was reviving, and bolsheviks would probably be removed from power.