In a case that triggered national debate about academic freedom, a UC Santa Barbara investigation has cleared a sociology professor of improper conduct for e-mailing students images that compared Palestinian casualties of Israel's Gaza offensive this year to Jewish victims of the Holocaust.

However, professor William Robinson said Thursday he was not satisfied with faculty and administrative findings that he should not be disciplined. Robinson wants a campus apology and an investigation of what he said were improper efforts to silence him.

In January, Robinson sent his class the images, along with a statement in which he described Israel's policies in Gaza as a slow-motion genocide. Two Jewish students dropped the class, saying that they felt intimidated by the e-mail. They also said that Robinson had violated campus policies.

Some Jewish activists alleged that Robinson's e-mail was anti-Semitic. Many academics and civil libertarians defended the professor, who is Jewish, and called the accusations and investigation an attack on academic freedom.

Cyndi Silverman, the Anti-Defamation League's Santa Barbara regional director, said the campus decision "creates a disturbing message that only the rights of faculty are to be respected, not the rights of individual students."