During World War II, the German occupied large parts of Europe, including the area of the Soviet Union where many Mennonite lived. They attempted to document the ethnicity of all Germans in occupied territory in order to grant them German citizenship. To accomplish this task, they collected family trees and life stories of all the ethnic Germans in German-controlled areas. The United States Army seized these records in 1945 at the end of the war and transferred them to the National Archives. Eventually the records were microfilmed and returned to Germany. Since then individuals have purchased many microfilms and donated them to various genealogy research centers, where they have been indexed. The indexes are online and can be searched, so this is an incredibly valuable record. They are called EWZ records, short for Einwandererzentalstelle or Central Immigrant Office.
There are a few caveats in order. First, applicants were attempting to prove German ethnicity so that they could receive citizenship from the occupying power, so they certainly had an incentive to shade the truth in some situations. Second, these documents were collected under wartime conditions and many church and family records had been destroyed first by Soviet repression and then by the vagaries of war. Sometimes people were recalling details from memory. Third, many Mennonites had been arrested or scattered before World War II and more were deported to Kazakstan in 1941 by the Soviets - since these were not in German-occupied territory, they did not apply for German citizenship during the war. Finally, not all microfilms with Mennonites have been purchased from the National Archives and donated to research centers and not all donated microfilms have been indexed. Despite these very real limitations, this is a fantastic research collection.
It takes a bit of knowledge to find the information you want. The place to start is the Odessa3 online library's search page. At the top of the page is Searching the Odessa Library. Enter your surname of interest or village name as the Query String. Make sure to select War Records as the Data Category. I put in "Fast" as an example below.
On this page, you'll want to click on CTRL-F to open a search box in your browser and then type in a given name or a village or some other keyword to search. In this case I'm trying to find out if there are descendants of Gerhard Gerhard Fast #45022 (b. ABT 1767) of Ladekopp in the database, so I enter Ladekopp as the search term. Of course, he was no longer alive by the 1940s, but perhaps some of his descendants who applied for German citizen during World War II (or their parents or grandparents) were born in Ladekopp. I found a number of results, but here is one that looks promising:
To order the files, there are a couple places that have the most. The Mennonite Historical Society of British Columbia has undertaken a massive project to scan many of the films, so they are a good placed to start. Plus they only charge 0.10 CAD per page. The Germans from Russia Heritage Society (whose index is on the Odessa3 page that we used) also has many films, but they charge 2.00 USD per page. The files generally run 10-30 pages, so it can add up if you are getting several files.
Now you should know how to search the indices. The next post will explain how to use the documents in the file that you will receive.