"I first heard about Chaim when I was a little girl, but I only started looking for him on the internet in 1999, shortly before my mother died," says Kristina, who lives in Cardiff. "I'd spend hours, whole days, trying to bring up his name But it was not until I found the Rotblatt family tree on Jewish.Gen in 2004 that I started getting anywhere."
The story goes back to 1919, when Chaim, a Polish Jew who was interred in Innsbruck for the duration of the war, tracked down his children to Dresden, where their mother had abandoned them in an orphanage.
Says Kristina: "When Chaim came to collect Ruth and her brother, Hans, he was a stranger to them - Ruth was only a year old when she last saw him. The matron strongly discouraged the children from going off with 'this Jew'. Chaim couldn't persuade them so he had to leave them there."
Ruth grew up as a Christian in Germany, but her Jewish blood nevertheless made her a target for the Nazis. It was a Jewish doctor who took her into hiding in Berlin in 1938. She fell in love with the doctor's son, Hans Werner, but although they both managed to get to Britain before the outbreak of war, he was too traumatised by the death of both parents at the hands of the Nazis to feel able to commit to marriage.
So Ruth married an Englishman and had Kristina and her sister before the union broke up and she married her old sweetheart, Hans Werner, giving Kristina a Jewish stepfather.
"But my mother never lost her longing to know what had happened to Chaim," says Kristina. "As she got older, she seemed to become more acutely aware of what it must have been like not to be able to get your children back."
Ruth had died by the time Kristina discovered through her internet searches that Howard Rotblatt, a nephew of Chaim, who had changed his name to Herman, was alive and living in New York. "As we exchanged information and photographs over the years I felt increasingly confident that my search was nearly over," says Kristina. "Herman's son Fred looked so much like Ruth's brother, and he had called his daughter Charlotte, which was my mother's middle name.
"In 2010 Howard and I both did DNA tests, and the results showed we were first cousins. My daughter Jane and I immediately went to New York to meet our long-lost Jewish family. They had known nothing of Chaim's first family, but were very pleased to meet us."
It was a huge surprise for Kristina also to discover she was related to David Ben Gurion - Israel's first Prime Minister was the cousin of Chaim's mother, Kristina's great-grandmother. "I wonder if my mother knew that subconsciously when she used to look at pictures of him in the '50s and say to me: 'He has such a nice face'!" she wonders.
A more poignant surprise came in the form of an old, yellowing photograph which had mystified the American family when they found it in Chaim's possessions after he died. "It was of an unknown little girl, and on the back of the photograph was written in Yiddish: 'My daughter aged three years old.'
"The clothing has been identified as being from around 1916, when my mother was three, and I see a great resemblance to this little girl in my own granddaughter," says Kristina.
Sixty years after first learning of his existence, Kristina was finally able to piece together the puzzle of what had become of Chaim since his six-year-old daughter sent him packing in 1919.The denied father had gone to Vienna, married and had two more children before going into hiding in Belgium during World War II. Although his wife was deported and perished, Chaim survived and after the war went to join his daughter in America. He died in New York in 1978.
For Kristina, visiting his grave brought her a longed-for closure. "What a long road this man had travelled to arrive at this place, and what a long road I had travelled to find him." she says. "I laid some stones on his grave and wished he could hear my thoughts: 'These stones are for your lost children, Ruth and Hans, and these are from the family you never knew - your grandchildren and your great-grandchildren."
