A statue of the school mascot, the Trojan, on the campus of the University of Southern California in Los Angeles. (David McNew/Getty Images)

The University of Southern California locked down Monday after a faculty member told her students during class that there was an active shooter on campus, according to police.

But police found no evidence of a shooter or any crime at the private university of 44,000 students in Los Angeles. The faculty member was detained for a mental health evaluation. 

The alert frightened many, coming the day after the deadliest shooting in modern U.S. history. At least 58 people were killed and more than 500 injured at a concert Sunday night in Las Vegas.

Police responded in force to the false alarm at USC. An alert was sent out minutes after a 911 call, warning people to shelter in place. The Daily Trojan, the campus newspaper, reported a SWAT team searched Fertitta Hall at the USC Marshall School of Business while helicopters hovered overhead. The paper quoted a student, Remy Porsella, who said he heard screaming and saw hundreds of people running out the doors of Fertitta Hall. “It was full panic,” Porsella told the Daily Trojan.

“The campus is safe,” said Mike Lopez, an officer with the Los Angeles Police Department. And the person who raised the alert was detained to determine her state of mind; he said an incident commander called it “an episode” she had had. 

“In light of what happened last night in Las Vegas this was — it was great that we were able to respond to a situation threat as a real, live situation, but luckily it wasn’t,” Lopez added. 

“Thanks to the rapid response of the USC Department of Public Safety and LAPD, we were able to quickly verify that there was no active shooter,” John Thomas, chief of the USC Department of Public Safety, said in a statement Monday evening. “It was reported a faculty member during class falsely told her students there was an active shooter in the building. The faculty member has been detained by the LAPD.”

Officer Irma Mota with the Los Angeles Police Department said there was a report of a shooting in a building at about 12:20 p.m. local time. But officials found no evidence of any threat. 

Within an hour or so, they were able to reassure the campus community.