After Heidrich Himmler realized many of his guys were being killed he invented the gas van.  Another name for gas van is Gaswagen The Einsatzgruppen put the Jews in the gas vans to die.  The transition from shooting to gas vans was not entirely successful.  Einsatzgruppen A used the gas vans in Riga and sometimes Estonia.  Einsatzgruppen B used the gas vans in Minsk areas.  Einsatzgruppen C used the gas vans in Ukraine.  Einsatzgruppen D used the gas vans in Crimea and Caucasus.

The killing was done in mass murders otherwise known as really big groups. The Einsatzgruppen did most of the killing.

Einsatzgruppen gas vans did not go so well the shooting was much more effective.  The shooting was done in big groups. After the killing was done the Jews were buried in mass graves.