Not sure if anyone can help on it, but I know that all german volhyniens were purged out the area and pushed to the Volga/Siberia region during 1915. And they stayed there at least until 1918. Some just came back later, few never came back.

Hello Gustaf,

you did not mention the name of your grandfather?

My understanding is that between 1915-1918 the Russian czar removed land ownership and banned Germans into exile for a brief period. But the Russian revolution ended his reign and the exile was reverted. If I remember correctly from Rink/Stumpp account of Volhynian history, some Germans simply returned to their homes. The farm land was slightly desolate, but could be reharvested. Your grandfather could have simply returned to Volhynia.

With communism going forward 1920 the government was "modernized". Therefore now there could be some sort of records in local branches, which could have ended up in state archives (novograd-volynsk, zhitomir).

You can find KGB and repatriation lists on SGGEE dated from 1930s with Rosin (Rosen) names.

The Siberian exile followed the Holodomor period 1932/1933. The deportation of my family, for example, happened in 1936. My understanding is this happened in just over a week. They were placed into trains to Kazakhstan in the summer, built a large barn, survived the winter, and built homes for everybody the next summer. So by end of 1937 their relocation had already finished.

If you think your grandfather could have been in one of those labor camps (Trudd armee), I think this would be >1940-1950. There is an open memorial website, where you can find names only in cyrillic: https://ru.openlist.wiki/Special:OlSearch?olsearch-run=1&olsearch-name-fulltext=%D1...