He lived in Slavyansk, was a supporter of the referendum on the independence of the Donetsk People’s Republic, later moved to the Kharkiv region and then to Poland. According to the investigation, he came to Russia from Latvia. An operational video was published in which Karmazin spoke presumably a memorised text saying that the Security Service of Ukraine (SBU) had threatened to kill his daughter. Karmazin was not allowed visits by his hired lawyer. He was initially charged with sabotage in connection with the burning of railway boxes responsible for signalling, centralisation and automatic interlocking. However, seven more counts were later added to the case – of training and facilitating sabotage, preparing to manufacture explosives, preparing for a terrorist attack, receiving training for terrorist activities, participation in a terrorist community and espionage. On 28 March 2024, Karmazin was sentenced to 25 years in a strict regime colony with the first six years to be served in prison and a fine of 700,000 rubles. In February 2025, during the consideration of the appeal against the sentence, Karmazin was noticed to have speech impairments. In a letter, he said that during the process of his transfer he was placed in a cell with broken windows.