Students say Matthew Harris, who is also a former lecturer, sent an email to his former philosophy department threatening to hurt faculty and staff.
Harris posted hundreds of videos online Monday, including one showing video of the mass shooting in Las Vegas and the massacre at Columbine High School.
Students who had Harris as a professor say the trouble began last year and exploded Monday as news of his latest threats spread on social media.
"I've been scared about this professor, this guy, for about a year since my girlfriend told me about the stories - how he treated their class, but also the threats he made after he got put on leave," student Nathan Robbins said.
Late Monday night, UCLA announced all classes would be held remotely.
"We do not have specific information that this individual is in CA," the university tweeted. "Out of an abundance of caution, all classes will be held remotely Feb 1."
UCPD is actively working with out-of-state & federal agencies on threats sent to some members of our community. We do not have specific information that this individual is in CA. Out of an abundance of caution, all classes will be held remotely Feb 1. We will keep you updated.— UCLA (@UCLA) February 1, 2022
"UCLA Police Department is aware of a concerning email and posting sent to some members of the UCLA community today and actively engaged with out-of-state law enforcement and federal agencies," UCLA said in a statement prior to canceling in-person classes.
A statement from the student body president posted to Instagram said that Harris is living on the East Coast and that there is no threat on campus.
Students who have seen the videos posted to Harris' YouTube channel say his actions are extremely concerning.