The University of Southern California has beefed up security measures following a campus shooting last week that wounded four people.

In a letter posted on the USC website, President Max Nikias announced the changes Tuesday morning.

Only students, faculty, staff and their guests will be allowed on campus between 9 p.m. and 6 a.m. Anyone entering the campus after 9 p.m. will be required to show identification and ID’s may be checked on the weekends at the campus entrances. The university statement said it would increase the number of campus public safety officers and yellow jacket ambassador security guards on the perimeter of the campus, as well as install additional surveillance cameras.

“USC continues to be a welcoming campus. The incident on Oct. 31 showed that we need to be more careful about the possibility that individuals who come on campus may jeopardize the safety of others,” wrote Nikias in the online statement’s Q&A section.

On Halloween night, an argument between two non-USC students outside a campus party turned into a shooting that hurt four people. Party organizers had been turning people away who didn’t have a student ID.

A 19-year-old man was arrested and has pleaded not guilty to attempted murder charges.

Because of the shooting, university officials announced party promoters won’t be allowed to stage events on campus or at nearby Fraternity Row. The Halloween party was hosted by the Black Student Assembly and promoted by a non-university firm. The BSA announced Monday it was suspending all future parties and social events planned for the rest of the semester.

Alison Kiss is executive director at the Clery Center for Security on Campus, a Pennsylvania-based non-profit. The group provides training on Cleary Act compliance for university and college campus security officials. The Clery Act requires campuses to disclose security policies, crime statistics and provide warnings to students about crime and threats. The organization last year held a training event at USC.

“One of the challenges in many of our cities where we have campuses is that there’s a kind of that desire to be an open campus that are really truly connected with the community,” Kiss said. 

Kiss complimented USC officials on the new security measures for using discretion to balance an open campus atmosphere with tighter security. She suggested USC sanctioned community events held on the campus start earlier in the day to avoid the 9 p.m. identification checks.

Many USC students welcomed the new security measures. Except some undergraduates living in the campus residential halls griped at the announcement that fingerprint scanners would soon be installed at dorm hall entrances. Students would have to scan their thumbs at the entrance of each dorm.

Roger Brown, a freshman business major, lives at Birnkrant Residential College on campus. He said it would be a pain to visit friends living at other halls.

“I do get the vibe that they really do want the students to be safe but I feel like this is going just a little bit overboard,” Brown said.

Brown said security guards have been standing at his dorm entrance to make sure students don’t hold the door open for other people. He said his parents warned him to watch his back while off-campus when he first moved to USC for school but Brown says he feels safe while on campus, despite the shooting on Halloween.

Most universities use student ID card readers to secure dorm entrances. Some, like the University of Pennsylvania, use keypads and pin codes. It’s not clear when the scanners will be operable at USC residential halls or what the university plans to do with the fingerprints it collects from students.

It’s difficult to generalize security trends on open urban campuses across the country, said the Clery Center’s Alison Kiss. But she said there is one general trend across all campuses.

 “In the last 10 years, the campus safety field has become a highly professionalized field,” she said.

More former cops and retired police chiefs are taking jobs as heads of college and university security departments and brining with them their expertise, high-tech crime fighting tools and strategic safety plans.

This story has been updated.