After the operation began in April 1941, a panel of doctors began visiting concentration camps to select sick and incapacitated prisoners for "elimination".
This panel included those already experienced from Aktion T4, such as professors Werner Heyde and Hermann Paul Nitsche and doctors Friedrich Mennecke, Curt Schmalenbach, Horst Schumann, Otto Hebold, Rudolf Lonauer, Robert Müller, Theodor Steinmeyer, Gerhard Wischer, Viktor Ratka and Hans Bodo Gorgaß.
To speed up the process, camp commandants made a preliminary selection list, as they had done in the T4 operation.
This left just a few questions to be answered, such as personal information, date of admission to the camp, diagnosis of incurable disease, war injuries, criminal referral based on the criminal code of the Third Reich and any previous offenses.
Names of ballastexistenzen (dead weight prisoners) were to be compiled and presented to the medical doctors for withdrawal from service, which included any prisoner who had been unable to work for a long time or was substantially incapacitated and would not be able to return to work.

Prisoners in the preliminary selection had to report to the medical panel but there was no proper medical examination; the prisoners were questioned about their participation in World War I and about any war medals they might have received.
Based on personnel and medical records, the panel decided how to classify each of the prisoners.
The final assessment was made using the information in the reporting form and was limited to the decision as to whether or not the prisoner would be steered toward "special treatment" 14f13.
The report form and results were sent for documentary registration at the T4 central office in Berlin.

Prisoners being considered for the preliminary selection were sometimes encouraged by the camp administration to come forward if they felt sick or unable to work.
They were led to believe they would go to a "recovery camp", where they would have light duties.
Many prisoners believed the lie and readily volunteered but, after they were gassed at the killing centers, the victims' belongings were sent back to the camp warehouse for sorting.
Prisoners learned the true reason for the selection and even prisoners with serious illnesses stopped reporting to the infirmary.

The first known selection took place in April 1941 at Sachsenhausen concentration camp.
By the summer, at least 400 prisoners from Sachsenhausen had been killed.
During the same period, 450 prisoners from Buchenwald and 575 prisoners from Auschwitz were gassed at the Sonnenstein Euthanasia Centre; Hartheim Euthanasia Centre was used to kill 1,000 prisoners from Mauthausen concentration camp.
Between September and November 1941, 3,000 prisoners from Dachau and several thousand people from Mauthausen and neighboring Gusen concentration camp, were gassed at Hartheim.
Prisoners from the Flossenbürg, Neuengamme and Ravensbrück camps were also selected and killed.
After November, another 1,000 prisoners from Buchenwald, 850 from Ravensbrück and 214 from Groß-Rosen, were gassed at Sonnenstein Castle and Bernburg.
From March to April 1942, some 1,600 women were selected at Ravensbrück and gassed at Bernburg.

The "medical reviews" are described in an excerpt from letters written by Dr. Friedrich Mennecke; during a selection at Buchenwald, Mennecke wrote to his wife;
Weimar, Nov. 25, '41 8:58 a.m.
Elephant Hotel

First there were 40 forms to finish filling out from a 1st portion Aryan, on which my two other colleagues had already worked yesterday.
Of these 40, I worked on about 15. ...
Then came the "examination" of the pat.[ients], in other words, an introduction to the particulars & comparison with the notations in the files.
We were not yet finished with these by noon because both my colleagues only worked in theory yesterday, so that I "post-examined" the ones who Schmalenbach (& I myself, this morning) had prepared & Müller, his.
At 12:00 we first took a lunch break. ...
Then we examined some more until around 4:00 p.m., in fact, I had 105 pat[ients], Müller 78 p
After the operation began in April 1941, a panel of doctors began visiting concentration camps to select sick and incapacitated prisoners for "elimination". This panel included those already experienced from Aktion T4, such as professors Werner Heyde and Hermann Paul Nitsche and doctors Friedrich Mennecke, Curt Schmalenbach, Horst Schumann, Otto Hebold, Rudolf Lonauer, Robert Müller, Theodor Steinmeyer, Gerhard Wischer, Viktor Ratka and Hans Bodo Gorgaß. To speed up the process, camp commandants made a preliminary selection list, as they had done in the T4 operation. This left just a few questions to be answered, such as personal information, date of admission to the camp, diagnosis of incurable disease, war injuries, criminal referral based on the criminal code of the Third Reich and any previous offenses. Names of ballastexistenzen (dead weight prisoners) were to be compiled and presented to the medical doctors for withdrawal from service, which included any prisoner who had been unable to work for a long time or was substantially incapacitated and would not be able to return to work.
Prisoners in the preliminary selection had to report to the medical panel but there was no proper medical examination; the prisoners were questioned about their participation in World War I and about any war medals they might have received. Based on personnel and medical records, the panel decided how to classify each of the prisoners. The final assessment was made using the information in the reporting form and was limited to the decision as to whether or not the prisoner would be steered toward "special treatment" 14f13. The report form and results were sent for documentary registration at the T4 central office in Berlin.
Prisoners being considered for the preliminary selection were sometimes encouraged by the camp administration to come forward if they felt sick or unable to work. They were led to believe they would go to a "recovery camp", where they would have light duties. Many prisoners believed the lie and readily volunteered but, after they were gassed at the killing centers, the victims' belongings were sent back to the camp warehouse for sorting. Prisoners learned the true reason for the selection and even prisoners with serious illnesses stopped reporting to the infirmary.
The first known selection took place in April 1941 at Sachsenhausen concentration camp. By the summer, at least 400 prisoners from Sachsenhausen had been killed. During the same period, 450 prisoners from Buchenwald and 575 prisoners from Auschwitz were gassed at the Sonnenstein Euthanasia Centre; Hartheim Euthanasia Centre was used to kill 1,000 prisoners from Mauthausen concentration camp. Between September and November 1941, 3,000 prisoners from Dachau and several thousand people from Mauthausen and neighboring Gusen concentration camp, were gassed at Hartheim. Prisoners from the Flossenbürg, Neuengamme and Ravensbrück camps were also selected and killed. After November, another 1,000 prisoners from Buchenwald, 850 from Ravensbrück and 214 from Groß-Rosen, were gassed at Sonnenstein Castle and Bernburg. From March to April 1942, some 1,600 women were selected at Ravensbrück and gassed at Bernburg.
The "medical reviews" are described in an excerpt from letters written by Dr. Friedrich Mennecke; during a selection at Buchenwald, Mennecke wrote to his wife;
Weimar, Nov. 25, '41 8:58 a.m.
Elephant Hotel

First there were 40 forms to finish filling out from a 1st portion Aryan, on which my two other colleagues had already worked yesterday. Of these 40, I worked on about 15. ... Then came the "examination" of the pat.[ients], in other words, an introduction to the particulars & comparison with the notations in the files. We were not yet finished with these by noon because both my colleagues only worked in theory yesterday, so that I "post-examined" the ones who Schmalenbach (& I myself, this morning) had prepared & Müller, his. At 12:00 we first took a lunch break. ... Then we examined some more until around 4:00 p.m., in fact, I had 105 pat[ients], Müller 78 p
Action 14f13