There's a very large park in Moscow called Лосиный остров ("Moose Island"), more of a forest really. On Sep 21st he went out for a walk in this park and around midnight called his relatives and told them he got lost. They called the police and the emergency services. Tried calling him back as well, but he didn't answer. On Sep 23rd his body was spotted from a helicopter that was involved in a search and it was ID'd by the relatives.
The rest of the article is fluff.
[0] https://en.wikipedia.org/wiki/Losiny_Ostrov_National_Park