Sergei Nikolayevich Kourdakov

Sergei Nikolayevich Kourdakov (Russian: Сергей Николаевич Курдаков; March 1, 1951 – January 1, 1973) was a former KGB agent and naval officer who from his late teen years carried out more than 150 raids in underground Christian communities in regions of the Soviet Union in the 1960s.[1][4] At the age of twenty, he defected to Canada while a naval officer on a Soviet trawler in the Pacific and converted to Evangelical Christianity.[5][6]
 via wikipedia

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Former KGB thug targeted Christians, then found Jesus’ love | God
An interesting article on him.

He is known for having written The Persecutor (also known as Forgive Me, Natasha), an autobiography that was written shortly before his death in 1973 and published posthumously.[7] Since its publication, it has been the source of varied criticism. More wiki info here