I had written in the previous entry:

"In fact, Salo Landeau, the second best Dutch player (after Euwe) was the only chess player I could find who died in a death camp (Auschwitz)."

Actually, Salo Landau's  wife and small daughter died at Auschwitz October 12, 1944. While Salo died in Gräditz March 31, 1944.

Then:

David Przepiorka, who won the first Polish championship in 1926, came in 1st at Munich in 1926 and  played in 2 Opympiads, was a victim of a mass execution near Warsaw in 1940. Though it's been also rumored that he died in a concentration camp.

Karel Treybal, born in 1885, was a victim of the 1941 Nazi occupation of Czechoslovakia, but I'm unsure in what form.

-SBC