Colorado authorities have arrested the man who threatened a mass shooting at UCLA, according to a report. The man's identity has not been revealed but the LA Times identified the suspect behind threatening UCLA with a mass shooting as Matthew Harris.

Harris is a former UCLA lecturer and postdoctoral fellow who made threats to the philosophy department and wrote an 800-page manifesto containing racist, misogynistic and anti-Semitic remarks.

"The material includes a video entitled ‘UCLA Philosophy Mass Shooting’ and an 800-page manifesto with specific threats towards some members of our department," a UCLA email sent to students this week said, according to the LA Times.

UCLA canceled in-person classes for Tuesday in response, holding virtual lectures instead.

Harris had posted about 300 videos to a YouTube account, with most of them being published on Monday, according to Newsweek. His account now features a message from YouTube stating the page was "terminated due to multiple or severe violations of YouTube's policy prohibiting hate speech."

Titles of videos he posted to YouTube include: "MURDER," "my racial angel I'm so glad you exist" and "im a p*dophile, ladies im a p*dophile," Newsweek reported.