 After the return, Hromádko joined the International and Organizational Departments of the Secretariat of the Central Committee of the Communist Party of Czechoslovakia ("ÚV KSČ"), where he utilized his management skills and experience in building conspiracy networks.Since October 1947, he was responsible for maintaining cooperation with communist infiltrators to the National Socialist party.In December 1947, Hromádko became the head of a newly created secret department, officially called Department of National Front ("Odbor Národní fronty").