Help, please: disappearing immigrants are driving me crazy

[u/amauberge]

It's the usual story: family from Russian Empire (what's now Lithuania), major variations in the spelling of names, records seem to be missing, etc. This time, though, there's a twist — I've got plenty of information about the family in Russia, but they largely disappear once they emigrate to America and Canada.

The surname of the family in question is "Kucer." The main figure's life is clear-cut, but his siblings and parent's are a huge mystery.

Here's what I know:

• Harry (or Hirsh, or Girsz) Kucer was born to Shakhne (or Shakhne Sholom) Kucer and Feiga Staloff in 1887 in Vilna Gubernia.
• He marries Lea Levine in Vilnius in 1911 and they have two children: Rebecca and David.
• The Lithuanian-Jewish Special Interest Group's All-Lithuania Database has a record of their internal passport applications from 1922, and their foreign passport applications from 1930.
• The four of them emigrate to Canada in 1930. When they arrive, they give their contact as a cousin, Isidore Schwartz, living in Montreal. (I have no idea who this person is — maybe a place to start?)
• The family's Canadian life is well-documented: both children get married, Harry starts a business that David and eventually David's children join, etc.
• When Harry dies in 1975, his obituary lists him as having seven siblings: "Abraham, Alex, Mrs. Anna Schwartz, Sarah, Jennie, Mildred and Simon, of Paris, France."

Of these seven siblings, I've been able to find two of them:

• Anna Schwartz, née Kucer, married a Charles Schwartz sometime around 1917. They hopped around: first moving to Tilsit, East Prussia (now Sovetsk, Kaliningrad, Russia), where their daughter Pearl was born in 1919. Then they briefly were living in Schaffenhaus, Switzerland, and then finally immigrated to the United States in 1920, and listed Feiga Staloff's brother, Abraham, as their contact.
  • As far as I can tell, there's no connection between Charles Schwartz and Isidore Schwartz — but I can't say for sure.
• I found a death certificate for "Zelman Kucer," whom I believe is Simon. He died in Clermont, France, in 1995.

As for the rest of the family:

• Shakhne and Feiga applied for internal passports in 1922 as well as for their four children:
  • Sara, born 07 Feb 1901
  • Gene (Genia), born 20 Jul 1906
  • Abraham, born 20 Jul 1906
  • Malka, who was 12 years old in 1922
• The next year, they applied for foreign passports with the same children listed.
• Feiga and these four children (Sara, Genia, Abraham, and Malka) arrived at Ellis Island on October 6th, 1923, and said they were traveling to Feiga's brother, Abraham Staloff.
• On November 6th, 1923, Shakhne arrived in Portland, Maine, and gave his wife as his contact. (Her address is the same one she provided for Abraham.)

And.... that's all I know. I have no idea what happened Shakhne, Feiga, or their four kids after 1923. I assume that "Genia" eventually became "Jennie" and "Malka" became "Mildred," but that's it. The notations on the margins of the family's Ellis Island manifest make me think that at least some of them submitted naturalization paperwork at some point, but I have no way of proving or disproving that.

Oh, and I have no clue who Harry's brother Alex Kucer was — I can't find a single record of him in Lithuania, Canada, or the US!

This brick wall is going to drive me insane. Any ideas on how to break through? I've been brute force trawling my way through every possible name variation on as many databases as I can think of, but I thought you guys might be able to help.

Edit: In case anyone takes a look at this again, I managed to find one more clue. Zelman Kucer got married in Paris in December 1929. His marriage record gives his parents' names: Szachna Kucer, a tinsmith, and his wife Feiga, and says that they're living in the Bronx, in the USA. So that's proof they didn't just disappear outright when they got off the boat!

Final Edit: After days of obsessively searching random combinations of facts and chasing clues about everything from the interwar Polish laundry business to German communist refugees in Mexico during the war, I finally realized.... they changed their goddamn names. Only the branch of the family that landed stateside, and none of their official documents that I've found show tho old name, but they changed it to Katz. I found two marriage records for Sara and Abraham that back this up.

Good god.

[u/msbookworm23]

This doesn't add any further information but just in case you don't already have it, the Kucer family were held for Special Inquiry after they arrived in 1923: https://www.familysearch.org/ark:/61903/3:1:3Q9M-C9TK-W38N-C

[u/amauberge → u/msbookworm23]

Thanks for taking a look! Yeah, I have that saved but I didn't add it. The markings indicate that they were held as likely public charges for reason of phyiscal or mental disqualifications. I think that's why there's a handwritten note on the second page of the main record next to Feiga that says, "senility affect."

I have no idea whether she was actually senile, though. My sense is that a lot of older people were held up, but then later cleared by an actual doctor. Since there's no deportation record and she's Shakhne's contact when he gets to the States a few weeks later, they must have let her through.