It seems the Ukrainian SBU has done some photo analysis on the Russian social media sites and match a killed Russian soldier to his own social media site.

Warning---graphic photos.

It was interesting that immediately after the heavy Donetsk airport fighti9ng 32 dead bodies were sent immediately to Russian and another over 30 were not recovered from the airport fighting. All were Russian citizens and it is thought the remaining killed and un recovered were also Russian citizens.

This individual seemed to be Russian SF recruited by the FSB.

http://inforesist.org/a-russian-spec...to-18/?lang=en