A Tuesday post on the college's website said campus police were “aware of social media threats” and were investigating. The university's statement didn't offer further detail, but it came after at least two users posted threats on the anonymous location-based messaging app Yik Yak.
One user threatened to “shoot every black person I see.”
Another said: “Some of you are alright. Don't go to campus tomorrow.” The message seemed to echo one that appeared on the website 4chan — a forum where racist and misogynistic comments are common — ahead of the deadly campus shooting at an Oregon community college last month.
The posts were widely disseminated across the Internet and local media.
Campus police Capt. Brian Weimer told The Associated Press additional officers were already on campus before the university learned of the threats. University police were working with other state and local agencies to ensure the campus was secure, he said.
The University of Missouri Board of Curators held an emergency session Wednesday evening amid racial tensions on the Columbia campus. Board member John Phillips emerged after the three-hour meeting and said, "Nothing to share tonight. There may be something tomorrow afternoon."
Park's arrest was the latest development in a tumultuous week for the flagship campus of the University of Missouri system.
The student government president's accounts of having racial slurs shouted at him from a passing pickup truck helped spark a weekslong protest movement. A graduate student went on hunger strike to demand the resignation of university system President Tim Wolfe over his handling of racial complaints, then more than 30 members of the Missouri football team went on strike in his support. Those developments came to a head Monday with the resignation of Wolfe, who had become the target of many of the protests. Hours later, the top administrator of the Columbia campus, Chancellor R. Bowen Loftin, was forced out.
A plaza that had been the site of a sit-in by protesters was entirely empty Tuesday night and only a handful of students were seen walking around campus. Police officers from the campus department and city of Columbia were on patrol.
David Wallace, a spokesman for the student government group Missouri Students Association, said the group asked university officials to cancel classes Wednesday in light of the threats.
Gaby Rodriguez, a senior, said she was at work when she heard about the threats.
“It's really disheartening and proves the point of why these protests and boycotts were necessary,” Rodriguez said. “I don't think I've ever felt this unsafe at Mizzou.”
Some students, faculty and alumni have said the protests and top leaders' resignations are the culmination of years of racial tension.
A sophomore student named Mylinda, who declined to give her last name, told Al Jazeera she had been at the university for two years and still hadn't had a black professor.
While among other recent events, members of the Legions of Black Collegians, whose founders include a recently retired deputy chancellor, said slurs were hurled at them by an apparently drunken white student while practicing for a homecoming performance.
The university has promised changes.
Chuck Henson, a black law professor and associate dean, was been appointed on an interim basis Tuesday as the university's first vice chancellor for inclusion, diversity and equity.
The university system's governing body, the Board of Curators, also announced a number of other initiatives, including more support for the hiring and retention of diverse faculty and staff and a full review of all policies related to staff and student conduct.
Al Jazeera and wire services