Columbia University has temporarily barred a vocal pro-Israel professor from campus, saying he repeatedly harassed and intimidated the school’s employees.

Shai Davidai, an assistant professor in the business school, has been a polarizing presence on campus since Oct. 7, 2023, when Hamas led an attack on Israel that has turned Gaza into a battlefield. He has accused Columbia of not doing enough to crack down on pro-Palestinian protests, which he says are broadly antisemitic and support terrorism. He often makes videos of student activists and administrators and posts them online, actions his critics say blow past the boundaries of civility and policy.

In recent days, Professor Davidai has used his X account, which has more than 100,000 followers, to accuse several student groups of supporting terrorism; posted the name and email address of a Columbia professor he suggested was “OK with rape, murder, torture and kidnapping”; and falsely called Rashid Khalidi, a respected Palestinian scholar at Columbia who is retiring, a “spokesperson for Hamas.”

Last week, on the one-year anniversary of the Hamas attack on Israel, Professor Davidai posted videos of himself following around Cas Holloway, the university’s chief operating officer, for several minutes with a camera and peppering him with questions about why pro-Palestinian protests were allowed on campus that day.

“How did you allow this to happen on Oct. 7?” Professor Davidai asked in the video, amid a bustling backdrop of pro-Palestinian chants and activism. He added, “You have to do your job. And I will not let you rest if they won’t let us rest.”

The school said it notified Professor Davidai of its decision on Tuesday.

Professor Davidai, an Israeli citizen, declined an interview request, but posted an expletive-laden video on social media on Tuesday night in which he suggested he would sue the university for its decision and that he was “not going anywhere.”