Hours before hundreds of Jewish students were due to celebrate Purim at the Chabad House of Stanford University, Rabbi Dov Greenberg received an email.
“The coming Holocaust 2.0?” said the subject line of the email that landed in the Chabad chapter’s general inbox on Monday.
To Greenberg, the message to Jews was clear.
“Don’t get together. We’re on to you. We know about you, and we’re coming for you,” the rabbi summarized.

