Prince Igor Constantinovich of Russia (Игорь Константинович) (10 June 1894 – 18 July 1918), was the sixth child of HIH Grand Duke Constantine Constantinovich of Russia by his wife Elisaveta Mavrikievna née HH Princess Elisabeth of Saxe-Altenburg.
Igor was born on June 10, 1894 and attended the Corps des Pages, an imperial military academy in Saint Petersburg. He enjoyed theatre.
During World War I, he was a captain in the Ismailovsky Guard Regiment and became a decorated war hero. However, his health was quite fragile: he suffered from pleurisy and lung complications in 1915, and even if he returned to the trenches, he couldn't walk quickly and often coughed and spat blood.
On 4 April 1918, he was exiled to the Urals by the Bolsheviks and murdered in July the same year in a mineshaft near the town of Alapaevsk, along with his brothers HH Prince John Constantinovich and HH Prince Constantine Constantinovich, his cousin Prince Vladimir Pavlovich Paley and other relatives and friends. His body was eventually buried in the Russian Orthodox Church cemetery in Beijing, which was destroyed in 1986 to build a park.
Source: wikipedia.org, regiment.ru