A group of four men had disappeared in August on a river-fishing expedition to the vast Yakutia region in the Russian Far East, one of the most remote and inhospitable places in the world.

Only two of the men were finally helicoptered to safety at the end of November and the discovery of fragments of a human corpse at their campsite prompted investigators to open a murder case amid rumours of cannibalism.

The two survivors have not been arrested but are being treated as witnesses in the murder case. However it appears investigators are now certain cannibalism took place.