They seem cold, disinterested, even disdainful, as they sift through the rubble or belligerently deny access to investigators. But who are the separatists? They are a loose group of ordinary Ukrainians and trained military personnel, who have formed a militia under the command of pro-Russian rebel commander, Igor Girkin. The separatists are concentrated in the eastern Ukrainian cities of Donetsk and Luhansk (also sometimes spelled Lugansk).