Ukrainian activist Oleksandr Kolchenko is serving a 10-year sentence in Russia on terror charges that human rights groups say are politically motivated. He was convicted in 2015 alongside Ukrainian filmmaker Oleh Sentsov after Russia's illegal annexation of Crimea. During a visit by an observation mission, Sentsov described the time he's spent in an isolation cell, as well as the letters of support he's received from inside and outside Russia.
