Although it is unknown if Kaplan either was part of the Ambassadors' Plot or was even responsible for the assassination attempt on Lenin, the murder of Uritsky and the failed assassination of Lenin were used by Dzerzhinsky's Cheka to implicate any malcontents and foreigners in a grand conspiracy that warranted a full-scale reprisal campaign: the "Red Terror". Thousands of political opponents were seized and "mass executions took place across the city, at Khodynskoe field, Petrovsky Park and the Butyrki prison, all in the north of the city, as well as in the Cheka headquarters at Lubyanka". The extent of the Chekist reprisal likely foiled much of the inchoate plans by Cromie, Boyce, Lockhart, Reilly, Savinkov, Filonenko, and other conspirators.