Joan Lefkowitz knows her parents and two of her sisters perished in Nazi concentration camps during World War II. She and other family members were lucky. They survived.

But the fate of her older brother, Alexander Braun, has gnawed at her for a large part of her 86 years.

The Miami Beach resident has been told her brother was taken from a labor camp in Hungary and marched toward Russia, but beyond that she’s heard only speculation.

”He disappeared,” said Lefkowitz, who was born in Czechoslovakia. “I would like to know what happened.”

On Sunday, her daughter-in-law, Terry Lefkowitz, filled out a request for any available information about her brother from the International Tracing Service archive in Bad Arolsen, Germany — a repository of more than 100 million documents collected by the Allies after the war.

The documents, mostly from Western and Central Europe, had been open to the public for some years after the war and then sealed until last November.