An Israeli Holocaust survivor died shielding his students from a mass murderer on the day that Jews who were mass murdered during World War II are remembered each year.

Liviu Librescu, 76, was an internationally renowned professor of aerospace engineering at Virginia Tech.

Librescu's son, Joe, who lives outside Tel Aviv, said his father "barricaded the door and blocked the shooter from entering. …This was typical of him. He did not fear death and at all times tried to do the right thing."

Librescu was apparently shot by a bullet that pierced the classroom door. His heroism gave students time to climb out the window, on the second floor of Norris Hall, said Sean Beliveau, a friend of the family who lives in Blacksburg, Va.

Beliveau said students have been e-mailing Librescu's widow, Marlena, to tell her of Librescu's courage.

Joe Librescu said his father was sent to an internment camp near Focsani, Romania, when he was 10.

After World War II, Librescu returned to the Romanian capital, Bucharest, where he studied mechanics and aviation construction. He was fired from Romania's aerospace agency when his employers discovered he was Jewish and a supporter of Israel, his son said. In 1978, Librescu was allowed to emigrate to Israel, where he taught at Tel Aviv University and the Technion in Haifa.

Librescu moved to Virginia Tech in 1985 for what was to be a one-year sabbatical but stayed after receiving a full-time position. A specialist in composite structures and aeroelasticity, he received many awards from around the world, including grants from NASA.

"His research has enabled better aircraft, superior composite materials, and more robust aerospace structures," said Ishwar Puri, head of Virginia Tech's department of engineering science and mechanics.

Charles Camarda, a NASA astronaut who got his doctorate in aerospace engineering from Virginia Tech, called Librescu "a brilliant professor. … He was also a gentleman … very statesmanlike, very articulate, just a pleasure to work with."

Rabbi Marvin Hier, head of the Simon Wiesenthal Center in Los Angeles, which combats anti-Semitism and other prejudice, said, "Destiny came knocking on his door. Any survivor of the Holocaust knows how helpless he felt. This man decided he would not let this act of evil occur. He was not going to be a bystander."

Joe Librescu called his father's death on Holocaust Remembrance Day "symbolic."

"Many circles closed along with his tragic death," the son said. "He died in the city he called home, where he loved what he did and what he stood for, and in front of his students, to whom he had dedicated his entire life."

Librescu's body was being flown to Israel for burial Thursday at a cemetery outside Tel Aviv.

Contributing: Yaakov Katz in Jerusalem; Traci Watson, USA TODAY; Associated Press

Enlarge By Librescu Family via AP Romanian-born lecturer Liviu Librescu and wife Marlena are seen in an undated photo. The Israeli lecturer was killed in the Virginia Tech massacre was a Holocaust survivor who later escaped from Communist Romania.