This was a German operation, supported by SS-Sturmbannführer Viktors Arājs’s Latvian collaborationist Sonderkommando 'Arājs', in the Biķernieki forest near Riga in occupied Latvia to execute Jews recently deported from Germany, Austria and occupied Czechoslovakia (15 and 26 March 1942).
As of 10 February 1942, the approximate populations of the ghettos and concentration camps in the Riga area were 2,500 in Jungfernhof concentration, 11,000 in the Riga ghetto and 1,300 in the Salaspils ghetto. Of the 12,300 Jews in the ghettos, about 3,500 men and 300 women were Latvians. In December 1941, Kurt Krause became the commandant of the Riga ghetto, with Max Gymnich as his deputy.
Altogether 20,057 Jews from the Reich had been deported to Riga, but by 10 February 1942 only 15,000 were still alive. In March 1942, the Nazi authorities in Riga decided that the ghetto had become overcrowded and organised a massacre which has come to be called the ‘Aktion Dünamünde’. The Nazis therefore ordered each of the groups in the ghetto to prepare a list of between 60 to 120 people for further ‘resettlement’, with the group from Berlin required to name 600 persons. The Nazis informed the Jewish leadership that the nominated people, who were to be drawn largely from those unable to work (the elderly, sick, and mothers with young children), would be transported to the fictional town of Dünamünde to work at a fish-processing facility. Created by SS-Obersturmführer Gerhard Maywald, the ruse succeeded, and many people were anxious to go, and on 15 March about 1,900 Jews assembled in the streets of the ghetto. The people were then taken by truck to Biķernieki forest on the northern side of Riga, where they were shot and buried in mass graves.