BERLIN - In early 1945, as he watched Berlin burn, Ernst Neugroschl couldn't help smiling.

The 17-year-old Slovakian Jew, was a slave laborer repairing damage to the capital, and the Allied bombs were raising his hopes that he would soon be liberated.

He and his parents had managed to stay out of Nazi hands until November 1944 when the SS caught up with them in Bratislava. The boy and his father were sent to the Sachsenhausen concentration camp on the outskirts of Berlin, then to a downtown subcamp in early 1945.

"One day, watching the city burn, I had a grin on my face until one of my friends hit me on the side and said, 'Take this grin off your face, or you'll be dead,'" Neugroschl, now 77, remembered in a telephone interview from his home in Silver Spring, Md.

As the Soviet army drew closer, the SS sent Neugroschl back to Sachsenhausen. On April 21, the guards took 33,000 of the remaining 38,000 inmates on a death march in which many were murdered or died from exhaustion. But Neugroschl stayed behind with his ailing father, and the next day the camp was liberated. A month later they found his mother. She was ill but had survived the Bergen-Belsen concentration camp.

Neugroschl went to Israel, became an engineer, and immigrated to the United States in 1957.

Today, he is still angry that Nazi war criminals like SS Capt. Alois Brunner - the man who sent his family to the camps - got away.

But he takes heart from the memory of one of his guards, an elderly retired police officer, who took him aside one day and asked him if he needed anything. A needle and thread, Neugroschl replied.

The next day the man told him to look in the bushes, where he found bread, kielbasa, needles and thread, "and it stuck in my mind that they were not all murderers."