Wikipedia has very sparse information about this man but at 76 years old even stumbling can become a fatal accident.

"Given the location"? What is it about a forest that makes you think the government was involved? Or do you mean that every death in Russia is a suspicious death?

If you were a native Russian, your would look out not for malice but rather for negligence and indifference on part of the authorities. Which is why I, for one, think the right question to ask is: how did it come that a person so evidently in distress could not be located quickly in a place like that? No doubt, Losiny Ostrov is a large park (it is about the same size as Pinnacles State Park in California), but it is surrounded on all sides by urbanized territory and should have excellent mobile coverage. Given that Chervonenkis had a phone on him, couldn't Search and Rescue have the mobile provider determine his location (qv. http://en.wikipedia.org/wiki/Mobile_phone_tracking) with at least the accuracy that would allow for a small ground team to find him?