A Jewish professor at University of California, Santa Barbara is under academic investigation and has been accused of being anti-Semitic for sending students an e-mail comparing Israel's offensive in the Gaza Strip with the Holocaust. Sociology professor William I. Robinson denied the claims on Thursday and portrayed the furor as a threat by Israel's supporters to academic freedom. Two prominent Jewish groups continued to demand that he apologize. On Jan. 19 Robinson, sent an e-mail to 80 students in his "Sociology of Globalization" class entitled: "parallel images of Nazis and Israelis." "Gaza is Israel's Warsaw - a vast concentration camp that confined and blockaded Palestinians, subjecting them to the slow death of malnutrition, disease and despair, nearly two years before their subjection to the quick death of Israeli bombs," Robinson wrote. "We are witness to a slow-motion process of genocide...."