Russia’s Penitentiary Service admits Sentsov’s Ukrainian citizenship, - lawyer Dinze. DOCUMENT Dmitry Dinze, the attorney of Ukrainian political prisoner Oleh Sentsov, who is serving his sentence in a high-security prison in Russia’s Yamalo-Nenets Autonomous District, made public a certificate issued by the Office of the Federal Penitentiary Service of Russia saying that filmmaker is a citizen of Ukraine. 20 074 55 Previously in trend: Ukrainian hostages in Russia