Until the end of the World War II, Catsch was a professional colleague of Soviet biologist, Nikolay Timofeev-Ressovsky at the Kaiser Wilhelm Institute for Brain Research in Berlin, studying on the genome and genetic structures.

[3] No later than 1942, he was at the Kaiser-Wilhelm-Institut für Hirnforschung (KWIH, Kaiser Wilhelm Institute for Brain Research)[4] of the Kaiser-Wilhelm Gesellschaft, in Berlin-Buch.

At the close of World War II, Russia had special search teams operating in Austria and Germany, especially in Berlin, to identify and “requisition” equipment, materiel, intellectual property, and personnel useful to the Soviet atomic bomb project.

In mid-May 1945, the Russian nuclear physicists Georgy Flerov and Lev Artsimovich, in NKVD colonel's uniforms, compelled Zimmer to take them to the location of Riehl and his staff, who had evacuated their Auergesellschaft facilities and were west of Berlin, hoping to be in an area occupied by the American or British military forces.

Born and Karl Zimmer were being held in Krasnogorsk, in the main PoW camp for Germans with scientific degrees, Riehl arranged though Zavenyagin to have them sent to Ehlektrostal’.

The institute in Sungul’ was responsible for the handling, treatment, and use of radioactive products generated in reactors, as well as radiation biology, dosimetry, and radiochemistry.

The institute was known as Laboratory B, and it was overseen by the 9th Chief Directorate of the NKVD (MVD after 1946), the same organization which oversaw the Russian Alsos operation.

[13][14] (Laboratory V, in Obninsk, headed by Heinz Pose, was also a sharashka and working on the Soviet atomic bomb project.

Other notable Germans at the facility were Werner Czulius, Hans Jürgen von Oertzen, Ernst Rexer, and Carl Friedrich Weiss.

In 1947, Timofeev-Resovskij was rescued out of a harsh Gulag prison camp, nursed back to health, and sent to Sungul' to complete his sentence, but still make a contribution to the Soviet atomic bomb project.

In fact, in Sungul', Catsch began his work on developing methods to extract radionucleotides from various organs, which he would continue when he left Russia.

Other colleagues of Riehl who worked with him in Russia also went West; Günter Wirths fled to the Federal Republic of Germany (FRG) and Karl Zimmer went legally.

In 1962, while still at the KFK, Catsch was appointed to the newly created Lehrstuhl für Strahlenbiologie at the Technische Hochschule Karlsruhe.