In the movie Der Untergang (Downfall), there is a scene where the "Greifkommando" execute civilians who attempt to flee during the Battle of Berlin. There is also another scene where civilians are hung in the streets with propaganda signs strung around their necks.
Who were these Greifkommando and what exactly were they tasked with? Were they all members of the SS? Were they created during the final phases of WW2? Are there any accounts of their actions?
'Greif' comes from 'greifen' - 'to grab'. 'Greifenkommando', therefore, just means 'grab detachment'. It's a job, not a distinct unit. By 1945, this would have meant any unit tasked with capturing deserting troops or civilians fleeing without permission.
In the first years of the war, this job would be undertaken by the Feldgendarmerie military police, and the Geheime Feldpolizei, the military counterpart to the infamous Gestapo. However, as desertion rates climb as the war begins to look bleak for Germany, the FG and GFP find themselves too busy dealing with partisans to keep track, so a special unit, comprised exclusively of 3 year veterans with at least a 2nd-class Iron Cross, the Feldjaegerkorps, is instituted. Drawing their authority directly from OKW, the FJK were empowered to summarily execute deserters.
However, this was Nazi Germany, and having one organisation to do a simple job would have made far too much sense, so in addition to the Army units, there were also Waffen SS units who took it upon themselves to punish deserters and 'cowards' - or, just as often, people who were unlucky enough to be caught behind the lines without a decent reason.