He was a member of the Sokolniki club, who were exploring the cave. Together with his diver partner Aleksey Aksenov he was on his way back from explorations beyond the 4th siphon. His dive partner tried to resuscitate him but he was unsuccesful.
Currently, participants of nearby expeditions (Kuybishevskaya, Voronya) are working together with the expedition team to extract the body from the cave.
Given the depth and many obstacles along the way (including a siphon), the rescue action is going to be long and difficult.
Our thoughs go out to all family, friends and fellow cave divers.