After his recovery, he continued with his studies and served as a provisional doctor on the Western Front until the end of the war in 1918, at which time he was decorated for valor and humanitarian service by three different countries, Finland, Switzerland and Germany.
In 1942, he wrote a memorandum expressing his objections to the Third Reich's development of such weapons, stating during his witness testimony at the Nuremberg Trials, "I personally made a report to Generaloberstabsarzt Handloser...
(Nuremberg document 619)[6] In 1944, Schreiber, who had grown increasingly aware of Göring's antagonism toward him, conferred with Dr. Karl Brandt, the attorney for the health care scientific advisory board about what to do.
[7] On 30 April 1945, while caring for the wounded in a makeshift hospital in the Reichstag Building in Berlin, he was taken prisoner of war by the Red Army and transported to the Soviet Union.
On 26 August 1946, the Soviets allowed Schreiber to appear as a witness at the Nuremberg Trials, to give evidence against Göring and Kurt Blome, who had been in charge of German offensive biological weapons development.
[4] Schreiber himself was not charged with any war crimes at the Nuremberg trials, although he was convicted in absentia by a Polish court of "conducting gruesome medical experiments" at Auschwitz.
Still under Soviet custody, he was later given the rank of starshina, and was ultimately offered the position of Chief Medical Officer in the newly formed East German Police Force, the Volkspolizei.
[9][13] Schreiber was subsequently hired to work with the Counter Intelligence Corps and beginning in 1949 was employed as post physician at Camp King, a large clandestine POW interrogation center in Oberursel, Germany.
A Janina Iwańska, who was being treated at Beth Israel Hospital in Boston, was shown a photo of Schreiber and asked if he was one of the scientists who had experimented on her at Ravensbrück concentration camp.
The second article, also by Drew Pearson, published on February 10, 1952 includes Schreiber's claim that he had never been to Ravensbrück nor any other concentration camp and that he never conducted or supervised any experiments on human beings.
That same article also includes a statement by the Air Force Surgeon General stating that he questions such accusations because Schreiber was not a defendant at Nuremberg, but a witness.
And from there, the Joint Intelligence Objectives Agency arranged visas for him and his family to move to Argentina, where another one of his daughters was living and had recently given birth to Schreiber's first grandchild.