Leonid Koehn (Кейн) was the "last" Mennonite living in Antonowka, or for that matter, probably all of Volhynia. Leonid (equivalent to Leonard in English) was born in 1935, a year before the deportation of the Volhynian Germans. We don't know how many Antonowka families were deported in March and Juen of 1936, but for instance, 30 families from Lilewa were evicted at this point (Згортання «коренізації» та відновлення політики репресій в середині та другій половині 30-их років ХХ століття, Валерій Ковальчук, Юрій Корзун). Probably little Leonid, along with his family, was swept up in this mass eviction movement.
We don't know where Leonid and his family were taken but many of the others from this area ended up in Kazakhstan, namely in the areas near Kellerovka and Kokshetau. These unfortunate souls were unceremoniously loaded onto train cars, shipped to the east, and basically dumped in the frigid steppe where they had to then fend for themselves. See various articles by Otto Pohl explaining the details of this inhumane action on the part of the Soviets.
The amazing part is that after a certain period of time (probably after 1953 - after Stalin's death), Leonid was able to make his way back to Antonowka! He lived with his family in Antonowka ever after, thinking that he was of Czech ancestry. Remember that, as the Mennonites vacated Antonowka in 1874, they were bought out by Czech settlers. The history of these Czechs can be found here https://www.volynaci.cz/. Leonid and his wife, Lyuba, were even interviewed for this article in 2002, saying that they were Czech (https://m.day.kyiv.ua/ru/article/obshchestvo/antonovskie-chehi?fbclid=IwAR0_jqa_SJasmwnhsqKnhyKOQdIm7LnqmXAIDccT4pIV3h8ujer8QmbRjxg).
We can be absolutely sure, though, that Leonid was German. And, given the number of Mennonite Koehns who came to USA from Antonowka in 1874, we can be almost certain Leonid was a relative.
Leonid's was Ernst Köhn, born 28 Feb 1893, and baptized in Karolswalde in 1912 under the authority of the local Lutheran parish. Ernst's father was named Andreas Köhn, maybe born in the 1890s. Honestly, there really isn't a more typical Antonowka Mennonite name than Andreas Köhn.
Many visitors from America after the fall of the USSR met Leonid, I've visited with several of them and they've said he was a kindly man who liked to talk. Shane Koehn, after a trip to Ukraine in 2007, says that Leonid seemed to be sick, perhaps with some sort of paralysis. However, Leonid's wife showed them the graves of Leonid's father, Ernst (1895-1980), and grandfather, Andreas, in the Antonowka cemetery at the west edge of the village.
In 2020, I corresponded a little with the Catholic priest in Ostrog, Father Vitold-Yodif Kovaliv, and he remembered burying Leonid in 2009. The priest still goes to the cemetery periodically to bless the graves there. We also know for a fact that Leonid had children and grandchildren and that some of these grandchildren, married into local Ostrog families, live today as Ukrainians probably completely unknowing of their Mennonite ancestry.