Galina Dzhugashvili, a granddaughter of Soviet dictator Josef Stalin who challenged accounts of her father’s internment at a Nazi prison camp, died Monday in a Moscow hospital. She was 69.

Her father, Yakov — Stalin’s eldest son — was a Soviet senior lieutenant who historians say died at the Nazis’ Sachsenhausen camp in 1943 after Stalin declined to swap him for a German general. Accounts disagree whether he committed suicide or was murdered. In 2003, American military officials presented Dzhugashvili with documents they said indicated her father was shot trying to escape. Recently, however, Dzhugashvili had argued that her father was never taken prisoner by the Germans — a sensitive issue because Stalin treated Soviet soldiers who surrendered or were taken prisoner as traitors. She alleged that he died in battle and that photographs and letters indicating he was at the prison camp were falsified as part of a Nazi plot.

She said that, had Stalin believed Dzhugashvili had surrendered to the Nazis, he would not have treated her as kindly as he did or told her that she looked like her father.