Then this year, just days before Holocaust Memorial Day, the identity of the man who saved her relatives emerged on Facebook.
Various family members were tagged in a Facebook post left by someone seeking to trace Mr Dornbusch’s descendants.
“With the power of Facebook, two of the different families hidden by this man and his descendants have now all reconnected,” Ms Hart’s granddaughter Emma Russell, 21, said.
Sara Bank-Wolf, 49, who lives in Israel, was the author of the post. Her father, Dov Feingold, and grandparents, Chaim and Sara, were among those hidden by Mr Riszko, she said.
She previously knew they had escaped the Przemsyl ghetto and been hidden by a righteous gentile, but his identity remained a mystery for decades. “It was haunting me over the years,” she said.
Then, unexpectedly, new information came to light. “Last Sunday night, I pulled my mum and said to her ‘are you sure we don’t know anything else?’
"She said, ‘all I remember is that Zaydee used to say the man who saved them married one of the Jewish people he saved and moved to New Zealand’.”
Ms Bank-Wolf contacted a Holocaust museum in New Zealand, which introduced her to Mr Riszko’s daughter who had a list of the 16 her father had saved.
Mr Riszko, who died in 1978, emigrated to New Zealand in the 1950s where he worked as a dockworker.
His Wellington-based daughter, Eva Woodbury, said she had never heard from those her father saved. “When people are traumatised, things get very difficult. They couldn’t remember my father’s name. I don’t know what it was,” she said.
Her Jewish mother Rennie Riszko, who died in 2011, was the one exception. One of the 16, she married Ms Woodbury’s father, with whom she remained for 35 years.
Ms Riszko later fell pregnant while in hiding and gave birth to a son, George, just weeks before liberation. “She was taken at night to my father’s cousin’s home where she gave birth.
“She was convinced they wouldn’t survive because bombs were raining down because it was just 23 days before the liberation,” Ms Woodbury said.
Her mother, she said, was “really traumatised” most of her life, particularly after Mr Riszko’s death in 1978.
Ms Woodbury said she cried when she first spoke to Ms Bank-Wolf. “I felt and felt the release of having my father honoured at long last.”
Now a group of descendants are looking to trace relatives of the 16 people Mr Riszko helped save - and hope to have his act of heroism officially recognised.
“There are all these people that we’re connected to that we’re now in touch with,” Ms Hart’s daughter, Julie Russell, said
“If this righteous gentile gets his rightful place at Yad Vashem, we will all go and pay tribute.”
The man was “a hero,” Ms Hart said. “By hiding Jews, he risked his life.”
Speaking to the JC over Zoom, Ms Hart was visibly overcome with emotion. “For my grandma, it’s been difficult hearing about all this, having to relive it at all,” her granddaughter said.
The survivor is fully vaccinated and said she has not felt afraid during the pandemic. “To be in lockdown is not a bad thing. In hiding, we were scared, but now we are not,” Ms Hart said.
Sara Bank-Wolf, 49, who lives in Israel, was the author of the post. Her father, Dov Feingold, and grandparents, Chaim and Sara, were among those hidden by Mr Riszko, she said. 
Now a group of descendants are looking to trace relatives of the 16 people Mr Riszko helped save - and hope to have his act of heroism officially recognised.