Changes

The killings were done in first and second waves, with the bodies buried in mass graves.  When the Soviet Red Army threatened and carried out counter-offensives to reclaim lost territory, special units made up of concentration camp inmates (''sonderkomandos'') would return to the sites, dig up the bodies, and burn them in mass pyres, destroying the evidence of their crimes.  The number of individual persons killed by the Einsatzgruppen has been estimated at a minimum of one million.

The killings were done in first and second waves, with the bodies buried in mass graves.  When the Soviet Red Army threatened and carried out counter-offensives to reclaim lost territory, special units made up of concentration camp inmates (''sonderkomandos'') would return to the sites, dig up the bodies, and burn them in mass pyres, destroying the evidence of their crimes.  The number of individual persons killed by the Einsatzgruppen has been estimated at a minimum of one million.