Former Director of the Baltic Centre for Dialogue of Cultures, listed as an independent expert of the Public Diplomacy Support Foundation. She was detained and taken into custody in July 2018 on charges of high treason in favour of Latvia, expressed in long-term cooperation with the Latvian security services, as well as declassification of an employee of the Russian Federal Security Service (FSB). Initially, she said that the reason for her prosecution was the photos from her wedding, which showed the FSB officer Maksim Denisenko, who did not hide his place of work, and which were sent to guests from Latvia and Lithuania. It later became known that the case involves the transfer to Latvian intelligence of secret documents allegedly obtained by Zimina's husband Konstantin Antonets while working as a lawyer in the Ministry of Economy of the Kaliningrad region. On 24 December 2020, Zimina was sentenced to 13 years in a general regime colony and a fine of 100,000 rubles. In 2021, the Russian-language propaganda portal Baltnews, owned by the Rossiya Segodnya news agency, ran several publications about the case, referring to materials that were apparently included in the criminal case, in particular screenshots of some correspondence that allegedly took place between Zimina and alleged supervisors from Latvian intelligence, who give her tasks to supply them with personal data of employees of Russian organisations that work in the field of international relations and participate in non-profit projects with the Baltic States. Zimina's father said that his daughter is constantly subjected to pressure in the colony: she is constantly placed in a punishment cell; warm clothes, a boiling pot and coffee have been taken away from her, and doctors refuse to provide her with help despite her constant illnesses due to hypothermia. In early August 2023 Antonina Zimina suffered from Quincke's edema in the colony. It took her more than twenty-four hours to get an ambulance. On 25 October 2024, Zimina opened her veins after she was asked to write an explanatory note for not cleaning her cell and not exercising.