RollkommandoHamann (Lithuanian: skrajojantis būrys) was a small mobile unit that committed mass murders of Lithuanian Jews in the countryside in July–October 1941. The unit was also responsible for a large number of murders in Latvia from July through August, 1941. At the end of 1941 the destruction of Lithuanian Jewry was effectively accomplished by the Rollkommando in the countryside, by the Ypatingasis būrys in the Ponary massacre, and by the Tautinio Darbo Apsaugos Batalionas in the Ninth Fort in Kaunas. In about six months an estimated 80% of all Lithuanian Jews were killed. The remaining few were spared as labor force and concentrated in urban ghettos, mainly the Vilna and Kaunas Ghettos.
Usually the unit arrived already after the local Jews were rounded up and gathered in a more secluded area, usually a forest or a distant field, by local Nazi authorities and "Lithuanian partisans." Sometimes small, temporary ghettos were set up for gathering the Jews from several nearby towns. Jews selected for executions were marched to the location, usually about 4–5 kilometres (2.5–3.1 mi) away from where they lived, and shot. Sometimes men were shot first, while women and children were executed towards the end of 1941. The corpses would be disposed of in pits dug in advance and the loot (clothes and other property of those killed) would be divided among the perpetrators. Such killings became known as "actions" (German: Aktion, Yiddish: Aktsiye).