As a little girl I was prohibited from wearing black boots: They reminded Dad of the Nazis and gave him nightmares about Lea. He never spoke of his older sister, and I learned not to ask him about the aunt I would never meet, to accept the mystery that we had "family who disappeared in the war."

With every passing year, my curiosity grew. Dad died in 1980 without saying much about Lea. I often visited or spoke with his last living sister, Jenny, who returned to Vienna after surviving the Theresienstadt concentration camp. Aunt Jenny was always thrilled to hear from me--but reluctant to speak of Lea. The only evidence Lea had ever existed was a photo of a young woman Jenny identified as her eldest sister, posed with an infant. For years I stared at the picture on my living room wall, haunted by the same dark eyes that I shared with my father. Who was the infant? What was the baby's name? What happened to them?

Over the years Aunt Jenny dribbled out a few more details: Lea was married and had three teenage sons. Her husband's family name was Marfeldt. My father escaped from Vienna to Switzerland in 1939 with his brother, Ello. Ello married a Swiss. His only child, Anita, is my lone first cousin. Although she lives in Switzerland, we are as close as the siblings neither of us had. We shared the pain of learning we had lost three cousins, the boys who vanished with our aunt. Jenny died in 1996 without adding to our slender list of facts about Lea.

It seems impossible in our information age that all record of a family could disappear. I searched the Internet and other electronic databases. I leafed through Red Cross documents, lists from Holocaust libraries and synagogues, concentration camp records, Jewish newspapers. I found no Marfeldts. I learned this was not unusual. Where the Nazis failed to incinerate an entire family, they often succeeded in wiping out many of its branches. I was determined, however. I wanted to record for future generations that these people had lived, that they mattered to our family. I hired a Jerusalem private investigator to search Israeli records. He fared no better than I.

Last December, I visited Anita in Switzerland. She had uncovered a small clue. My Uncle Ello, who died in 1961, had left voluminous personal papers. In them was a postcard from Lea, with a 1942 postmark from Tarnow, Poland. We had always assumed she lived in Vienna! Lea wrote that she appreciated a package she received from relatives and needed warm shoes for her son Fritz, with whom she hoped to remain.

So we had a cousin named Fritz and he lived in Tarnow during the war. His last name was not Marfeldt but Marfeld. Further digging in Ello's papers yielded more postcards from 1943. Fritz wrote that he had heard nothing from his parents and brothers in six months and thought of them constantly.

I spent the 2000 winter holidays in Egypt and Jordan with my husband and children. At the last minute we decided to spend the final two days in Israel. While my family toured the Negev, I visited the library at Yad Vashem, a Holocaust memorial site in Jerusalem. My last shot, I thought. I found a database called Pages of Testimony with the names of millions of Holocaust victims. Everyone with knowledge of Holocaust deaths is urged to contribute, each swearing their testimony is correct. Eventually this database will be accessible via the Internet.

I typed in "Marfeld." A name appeared on the screen: Lea Marfeld. A miracle! Her page said she was from Tarnow and died in a concentration camp. There were pages for Fritz, dead at age 20, for Martin, dead at 18, and Simon, dead at 12. All lived in Tarnow. All died in concentration camps. I was more stunned to learn that each of my relatives had been entered into the Pages of Testimony on May 24, 1999, by a Jacov Zedon. I had never heard of this man. What prompted him to enter the Marfelds? And why so long after their deaths?

Zedon's telephone number was on each page. I used the library phone to call. A woman answered. I do not speak Hebrew. In the fractured German of my youth, I explained what I wanted. After a long silence she said, "I am so sorry. But my husband, Jacov, died last week. I never heard him speak of the Marfeld family. I had no idea that he entered their names at Yad Vashem." All she could offer was the phone number of Jacov's cousin.

I took it, sure that Jacov Zedon had taken Lea's story to his grave. A man appeared at my elbow. "I overheard you on the phone," he said. "My German is as bad as yours." This was Tommy Lamm, a professional researcher searching for Nazi war criminals on behalf of the Simon Wiesenthal Center in Los Angeles. He urged me to keep digging. "Just when you think that you've reached the end of the road, another road invariably opens up," he said.

Tommy spoke Hebrew. He offered to call Jacov's cousin. The cousin said he had never heard of the Marfelds. Jacov grew up in Tarnow, he added, and he referred us to a doctor who kept track of former Tarnow residents in Israel. The doctor could give us only a phone number for Lucia Melloch, who had lived in Tarnow and had immigrated recently. Tommy made the call because Lucia spoke Polish and Yiddish, and I speak neither. "I am in the library of Yad Vashem with an American woman searching for relatives from Tarnow," he began in Yiddish. "Have you heard of the Marfeld family?" His face lit up. I listened in amazement as he translated her reply: "Was the mother Lea, and the children Fritz, Martin and Simon?"

"Yes, yes!"

"My father owned a house in Tarnow during the war," she said. "We rented rooms to the Marfeld family." Since Lucia also spoke broken German, I got on the phone. Lucia was the same age as Fritz, 20, and they became good friends when the Marfelds moved into her father's house. Lucia said Lea's husband, whose first name she did not recall, taught Hebrew in the high school. Lea was a tall, kindly woman. Her sons were smart and well mannered. When war came, the boys had to leave school and try to survive when there was almost no food or clothing. In 1942, all but Fritz were taken by the Nazis. He was taken in 1943, shortly after writing a final card to Uncle Ello.

Lucia believed that they all went to nearby Belzec, the most deadly Nazi extermination camp. If Belzec is not as well known as Auschwitz, I learned from a book at Yad Vashem, it is because of approximately a million Jews sent there, precisely two emerged alive.

I also learned that German troops occupied Tarnow on Sept. 8, 1939. Jews were seized for forced labor, robbed, beaten. The Germans torched most of Tarnow's synagogues. In the ensuing months Jews lost their jobs and were stripped of money and property. On June 11, 1942, hundreds were murdered in the streets and 3,500 went to Belzec. By June 18 another 10,000 Jews had vanished into Belzec. Many more were slaughtered in the cemetery or in huge pits outside Tarnow. A Jewish ghetto was established on June 19, and in November another train with 2,500 went to Belzec.

Lucia last saw Fritz in 1943. His last postcard is postmarked March 9, 1943. According to the Encyclopedia of the Holocaust, killing continued in Tarnow until the end of 1943, when the city was declared judenrein ("cleansed of Jews"). I have no doubt that Lea, her husband and three sons were murdered, if not in Tarnow then surely in Belzec.

Belzec is an almost forgotten place, millions of unburied human bone fragments shrouded by an overgrown forest. I am saddened and disgusted to imagine the Marfelds' last thoughts, their un-mourned bones scattered in such a place. Small wonder that my father and aunt wished to spare their children such horror.

I asked Lucia, now 77, if she knew why Jacov had posted the names at Yad Vashem. "Jacov and I went to school together in Tarnow, and were great friends," she replied. "When I came to Israel, I wanted to make sure that the Marfelds and what happened to them were memorialized. Jacov lived closer to Yad Vashem, so I asked him to go there and enter the names." So Jacov's widow never knew the Marfelds--because her husband hadn't known them. He had merely done Lucia a favor. But why bother? "I always imagined that one day Lea's family would find her through Yad Vashem," Lucia said.

Two strangers half a world away tried to venerate a family that had been dead for more than half a century--and fate conspired to place these all-but-forgotten names before one of only two people in the world who cared about the Marfelds. The names went into the database in 1999. I came to Yad Vashem a year later. Had I visited before they were entered, I would have missed them, and probably stopped looking. Had I visited another day, would I have found a multilingual researcher to translate? A year later, would Jacov's widow still be alive? Would Lucia?

I used to fantasize that my relatives had escaped and were safe in Australia, or perhaps South America. Now I know that they are with the 6 million Jews who died during the Holocaust. I find peace in this awful truth and in knowing that they were never forgotten. And I know that one day my daughter Julia, sweet and kind and towering over her tall father, will look through dark eyes like Lea's at her own children, and tell them of her tall great aunt and of Fritz, Martin and Simon, her first cousins once but forever removed.