Code-named GT/COWL, Vorontsov was a Second Chief Directorate officer who had volunteered to spy for the Central Intelligence Agency by dropping a sheaf of secret documents into the car of an American diplomat in late 1984. He was arrested by the KGB in March 1986, and his CIAcontact, Michael Sellers, was detained while on his way to a rendezvous in Moscow and expelled. Vorontsov had been identified as a spy by Aldrich Ames.