The SD first established its power in Latvia through Einsatzgruppe A, which was subdivided into units called Einsatzkommandos 1a, 1b, 2 and 3. As the front line moved further east, Einsatzgruppe A moved out of Latvia, remaining in the country only a few weeks, after which its functions were taken over by the "resident" SD, under the authority of the Kommandant der Sicherheitspolizei un SD, generally referred to by the German initials of KdS. The KdS took orders both from RSHA in Berlin and from another official called the Befehlshaber (commander) der Sicherheitspolizei und des SD, or BdS. Both the KdS and the BdS were subordinate to another official called the Ranking (or Higher) SS and Police Commander (Höherer SS-und Polizeiführer), or HPSSF. The lines of authority were overlapping and ambiguous.Ezergailis, The Holocaust in Latvia, at page 253 The eastern part of Latvia, including Daugavpils and the Latgale region, was assigned to Einsatzkommandos 1b (EK 1b) and 3 (EK 3). EK 1b had about 50 to 60 men and was commanded by Erich Ehrlinger.
