It appears you are referring to a news event. Although I don’t have real-time capabilities to keep up with current news, as of my last update, several anti-Kremlin Russian activists have indeed joined the fight on Ukraine’s side against separatist forces that are backed by Russia. This started after annexation of Crimea by Russia in 2014. Some of these activists might have been killed in action, however for specific cases, please refer to the most recent and trusted news sources.
