Colonel Dmytro Kozyura, the former chief of staff of the SBU’s Anti‑Terrorist Center, was arrested in February 2025 following a counterintelligence operation code‑named “Rat.” He was accused of working for Russia’s Federal Security Service, or FSB, and later admitted in court that he had collaborated with the agency since 2018. Prosecutors said Kozyura passed classified information on Ukraine’s critical infrastructure, air‑defense plans and positions, and the aftermath of Russian missile strikes, including casualty figures. Investigators say he was recruited by the FSB in Vienna in 2018 and reactivated shortly before Russia’s full‑scale invasion in February 2022, maintaining regular encrypted contact with his handlers. Ukraine’s security service said the case involved a lengthy internal counterintelligence operation that allowed the SBU to feed disinformation to Moscow while documenting Kozyura’s activities. His detention was first reported in February 2025, highlighting concerns over Russian penetration of Ukrainian institutions during the war. Kozyura was convicted by the Shevchenkivskyi District Court in Kyiv of high treason under martial law and related offences and given a life sentence with the possibility of appeal under Ukrainian law.