Tracing possible Jewish ancestry — great-grandmother, a mysterious “Rabbi,” and oral history clues

Hello, everyone.

I’m seeking advice as I try to piece together the origin story of my maternal great-grandmother, whose life holds several unusual and possibly Jewish elements. My mother, now 76, grew up in the Zona da Mata region of Brazil and remembers intriguing details about her grandmother — details that were never fully explained but that now seem significant.

Here is what we know:

1. My great-grandmother, Maria Quintina da Silva, reportedly came to Brazil as a child around the late 1800s or early 1900s. Family stories suggest she became separated (her parents died probably) from her biological family during the voyage and was “adopted” (possibly informally) by a man named José Quintino da Silva. In practice, she lived more as a servant than a family member.
2. As an adult, she married very young and remained in the rural area.
3. Luckly, several stories survived:
   • A man she called “Rabbi” (or something very similar) used to visit her periodically. He always dressed in black and wore a short-brimmed hat. They spoke in a strange language that my mother described as “backwards”—which now makes me wonder if it was Yiddish or Hebrew. These conversations lasted for hours, and my mother says her grandfather didn’t like this man, referring to him as a “boring gringo.”
   • She kept a Star of David on the door of her house.
   • She made what my mother remembers unleavened bread and followed some dietary customs she never explained.
4. Recently, I made another discovery: there is no record of her death in the civil registries of the city where she supposedly died. This absence deepens the mystery. She may have died without formal registration, under a different name, or even in another locality.

I’m an archaeologist by training and now feel a deep need to reconstruct this part of my family’s history — especially while my mother is still here to recall these memories. I’ve done a MyHeritage DNA test, which shows Iberian, Italians, North African, and Middle Eastern ancestry, but no clear “Jewish” label, which I understand is common for people with Sephardic or converso heritage.

Have you encountered similar cases in Brazil or elsewhere? Are there historical resources, archives, or community paths that could help me explore whether my great-grandmother had Jewish origins — or was part of a hidden or reconnected community?

I deeply appreciate any thoughts, sources, or guidance from this community. Thank you!

I sorry if I am asking this in the wrong place. I checked the guidelines but I could not find anything about this type of inquiry,