Mr. Schwartz grew up roughly 155 miles east of Budapest in a woody Hungarian hamlet called Baktaloranthaza, where he worked for his father, a cosmetician known for his lavender perfumes and lotions. The local pastor used to let young Laszlo ring the church bells. They were so heavy, Mr. Schwartz remembers, that his tiny body was hoisted off the ground whenever he failed to let go of the rope in time.

All changed when Nazi Germany occupied Hungary in March 1944. For the next month, before Mr. Schwartz and his family were taken to the Kisvarda ghetto near the Ukrainian border and then later to Auschwitz, the sound of the bells was met with bellicose, anti-Semitic chants.

Mr. Schwartz said that after his encounter with Mengele at Auschwitz, he was assigned to the children’s barracks, but 11 days later he managed to smuggle himself onto a train carrying forced laborers to Dachau and its subcamps in southern Germany.

He spent the next year hauling sacks of cement for railroads and airplane bunkers — and today speaks almost fondly of the move, seeing in it his salvation.

BUT as the Nazis’ prospects for the Endsieg, or final victory, faded, Mr. Schwartz was swept up in one of the last-ditch attempts by the SS to kill large numbers of prisoners. For three days, Mr. Schwartz and about 3,600 other passengers languished without food or water on board a “death train,” before it halted unexpectedly in rural Bavaria.

“Suddenly I see one of the SS removing his uniform, putting on civilian clothes, and he waved to us,” Mr. Schwartz said. “ ‘Ihr seid frei!’ he said. ‘You’re free!’ ”

Mr. Schwartz dashed toward a nearby farmhouse, but he said his escape was thwarted when a bullet penetrated his upper neck and exited his right cheek, leaving a gaping hole in the side of his face. He had no option, he said, but to follow the gunman, a teenager from the Hitler Youth, back to the train.