Based on data which he indicated formed part of his CNSAS file, Tismăneanu also specified that he was the object of constant Securitate surveillance after his departure, that his mother was subject to pressures, and that derogatory comments on him, including a coded reference to his Jewish background ("tunărean"), were gathered from various informants and agents. He made mention of the fact that, according to the documents (the last of which were allegedly compiled in April 1990), the post-Revolution Foreign Intelligence Directorate had continued to monitor him. Tismăneanu also indicated his belief that the author of a denunciation note, who used the name "Costin" and recommended himself as a Faculty of Sociology professor, was the same person who, after 1989, had sent a letter to his University of Maryland employer, in which he had called attention to the communist activities of Leonte Tismăneanu (according to Vladimir Tismăneanu, the letter was dismissed as "abject" and irrelevant by its recipient). Tismăneanu also cited Costin's report to the Securitate, which expressed concern that his doctoral thesis was a covert popularization of the Frankfurt School and its reinterpretations of Marxist thought. According to his former colleague Radu Ioanid, the Urban Sociology Department group had been under constant Securitate surveillance, especially after Tismăneanu defected. Ioanid quoted his own Securitate file, which, in a post-1981 comment, referred to his "close contacts" with Tismăneanu, defining the latter as "a sociologist of Jewish nationality, a former office colleague Ioanid's, presently an outstandingly hostile collaborator of Radio Free Europe has settled in the USA." Ioanid also referred to Tismăneanu's family in Romania having been "heckled" by the Securitate, especially after he himself had been made suspect by his historical research into Romanian antisemitism.