The terrorist was detained while attempting to cross the administrative border between Crimea and mainland Ukraine, Censor.NET reports citing the press service of the agency.
Sosna is an active partner of the creation of the Donetsk People's Republic.
He participated in the fighting on the side of the separatists in the Donetsk region, conducted the overall coordination of the terrorist informants, summarized their intelligence findings and passed them to the leaders of Vostok (East) battalion for use in operations against the Ukrainian forces.
In addition, Sosna tried to organize export to Russia of early warning radar system Kolchuga (Chainmail) captured by the terrorists in Donetsk at Topaz Company.
In May-June 2014 he was directly responsible for sending Donetsk separatists to Russian GRU (The Main Intelligence Directorate) combat training camps, the Ukraine Security Service notes.