The suspect whose online threats forced UCLA to host all Tuesday classes remotely has been arrested in Boulder, Colorado, multiple law enforcement sources familiar with the investigation told NBC News' investigative unit.
UCLA's in-person Tuesday classes were canceled after the suspect, identified by Boulder police as Matthew Harris, made threats against the campus and the department members.
"I am greatly relieved to share that law enforcement officers in Colorado have taken into custody the individual who made threats against some members of our UCLA community yesterday," the school's administrative vice chancellor Michael Beck said in a statement to the UCLA community.
"While we will continue with our plans to keep instruction remote today, with this development, we will return to in-person instruction tomorrow."
UCLA police were working with out-of-state agencies to gather more information about the threats and the individual who sent them. NBC's investigative unit also confirmed the Federal Bureau of Investigation is aware of the situation.
As of 6:45 a.m. Tuesday, a UCLA spokesperson told NBCLA, "out-of-state law enforcement has confirmed that the person who made threats to UCLA is under observation and not in California. Classes will remain remote today."
Official law enforcement sources have not yet released the name of the man arrested in Colorado, as of 11:30 a.m. Tuesday.
However, Los Angeles Police Department Chief Michel Moore told NBCLA on Tuesday that it previously had contact with that man, now suspected of posting a mass violence threat against UCLA.
Moore said the LAPD's Mental Evaluation Unit, or MEU, had contacted the same individual some time in the Spring of 2021. The exact nature of the contact was not immediately released.
The Mental Evaluation Unit is called to assist with individuals who may be experiencing a mental health crisis, and can sometimes divert a person who’s been arrested to treatment, rather than jail, depending on the circumstances.
Monday night, NBCLA received a statement from the school, saying university police were 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.''
According to Nathan Robbins, a junior who spoke to NBCLA on Monday night, the threats included a video referencing a mass shooting. Robbins says his girlfriend was one of the people to receive an email with a link to the video from a former UCLA researcher and guest lecturer.
"He emailed her old class with this weird threat, including like a link to a video about mass shooting with himself in it so— basically threatening to come shoot up the school," Robbins said.
"It's really terrifying, honestly," he added.
According to a report by the Los Angeles Times, the threatening emails -- sent to several people at UCLA -- also included an 800-page manifesto containing violent threats to specific individuals and racist language.
It was followed up by a post stating in-person classes on UCLA's campus will be held remotely Tuesday.
"I want to inform you that UCLA Police Department is aware of a concerning email and posting sent to some members of the UCLA community today," Beck said in a statement to students.
Some students appeared stunned by the news of the video and manifesto, and expressed concern -- before in-person classes were changed to remote classes -- that they had to wait to receive an official statement from the school to be able to stay off-campus in favor of personal safety.
“It's definitely hitting hard,'' Kahlila Williams, a senior, told NBC 4 on Monday night. "I cannot, financially, miss my hours" at school and her job, she explained. "It's just like... it's a conflicting decision. It's just really hard."
Beck addressed that fear and difficulty in his statement Tuesday, after the man was taken into custody.
"The threats made yesterday were frightening for many of us and caused our community to feel vulnerable at an already challenging time," he said, in a message that also offered counseling resources to those at UCLA who might need it. "These are unsettling times and your well-being is a top priority, so please do not hesitate to reach out for help if you need it."
"I offer my deepest thanks to UCPD and other law enforcement agencies for thoroughly investigating these threats as soon as we learned of them and for coordinating to locate and arrest the individual in Colorado," he continued.
"I also want to thank all of you for checking in on those around you. Compassion and care for one another are the hallmarks of a true community."