Polish jews escaping to Dzhamboul

Hello, i suppose it's coincidence, but since i also got to this page looking for a Polish-Russian Jewish KNOPF family in Kazakhstan...
The Knopf family I'm looking for hid their jewishness, the patriarch Jakob David Knopf had converted to Lutheranism before WWII, but he and his sons were sent to Stalinist labour camps apparently b/c of their German surname. One son had a daughter Private but the family's jewishness was apparently hidden from her.
After the labour camps they were sent to Semipalatinsk where they worked as engineers/architects and mathematicians. Communication (letter-writing) with them was broken off when the sisters left Poland for Israel, and no source (e.g. red cross) has yet been able to find them or traces of this Knopf family in Kazakhstan...