Damian Omelianenko was first detained by Russian military personnel on 24 May 2022. His tattoos, discovered during examination, were regarded as a "symbol of Nazism." For nearly a month he was unlawfully held in a basement, where he was constantly tortured, including with electric shocks and beatings with sticks. After his release on 22 June 2022, his relatives reported that he had been beaten. Damian, his brother, and his grandmother were placed under surveillance. Omelianenko was detained for the second time on 16 November 2022.

Damian was first unlawfully detained in Melitopol, then transferred to Simferopol Pre-Trial Detention Centre No. 1. He was later held in an overcrowded cell at Rostov Pre-Trial Detention Centre No. 1, where he was kept together with 27 other detainees. Beginning 24 April 2024 he was held in Taganrog. During his time in detention, Omelianenko lost about 30 kilograms due to a stomach ulcer and the absence of medical care. In Taganrog, letters from his mother were not delivered to him, creating a complete information vacuum. However, the chronology indicates a possible transfer to Mariupol at the end of 2024, which is why his current whereabouts are listed as requiring confirmation.

Omelianenko was initially charged with organising and participating in a terrorist organisation under Part 2 of Article 205.4, Part 2 of Article 205, and Part 3 of Article 205 of the Russian Criminal Code. On 30 April 2025, the Russian Prosecutor General's Office approved the indictment in the criminal case against Damian Omelianenko and Artur Shashenok. By the time of the first hearing, additional charges had also been brought against him, in particular under Part 4 of Article 222.1, Part 1 of Article 361, and Part 3 of Article 361 of the Russian Criminal Code. However, the specifics of all the charges require further clarification.

Along with Damian Omelianenko, Ukrainians Artur Shashenok and Oleksii Makarenko have also been charged in this case. According to investigators, in the summer of 2022, Omelianenko joined a terrorist organisation to plan a series of explosions in Berdiansk. Investigators allege that he tracked Oleksandr Kolesnikov, the deputy head of the State Inspectorate for Road Traffic Safety, and passed information on about him, after which Makarenko detonated an explosive device targeting the police officer when he approached his car near his house. Kolesnikov later died in the hospital. The accused are also charged with the murder of Oleh Boiko, deputy head of the occupation military-civil administration of Berdiansk, and his wife Liudmyla; an attempted assassination of the "military commandant of the city", Artem Bardin; and an attempted assassination of the deputy head of the occupation administration.