The University of Missouri says it is investigating threats made on social media and has increased security on campus but refused to cancel classes.

The reports of threats and intimidation came after days of protest at Mizzou, as students demanded the President step down for his ineffectiveness of handling racial issues on campus. On Tuesday night, the university announced that it had increased security in response to the threats.

MUPD is aware of social media threats and has increased security. Investigators are currently working the case. — MUPD (@MUPDpolice) November 11, 2015

On Tuesday, the University of Missouri Police Department said it confirmed that a “phoned-in threat” was made earlier in the day to the Black Culture Center on campus. The building doors were locked, and the facility was searched, but nothing suspicious was found, authorities said.

Threats were posted to the messaging service, YikYak, in which someone said they would “stand my ground and shoot every black person I see.”

The Twitter account for the Missouri Student Association, the undergraduate student government at the University of Missouri, posted the following screenshots from YikYak:

Early Wednesday morning, police announced the suspect was in custody.

MUPD has apprehended the suspect who posted threats to campus on YikYak & other social media: https://t.co/HcjpmzLqAC — MU Alert (@MUalert) November 11, 2015

Black students from the university began to evacuate from campus after a series of racist confrontations.

students are calling upper classmen asking to stay at their apartments. This is @Mizzou. They don’t feel safe in the dorms. — Jalen (@jalenmosby) November 11, 2015

Students took to social media to share their accounts.

The cops are holding this white guy back he is in speaker circle screaming me jaylah and obehi had to run to the car — Hailey (@mariehaileyy) November 11, 2015

If you are black and on campus GO HOME there is a racist meeting in speaker circle they are threatening us saying dont come tmmrw — Hailey (@mariehaileyy) November 11, 2015

Im about to cry if you are on campus go home its not worth it. I just had to run this white guy was screaming saying he has had enough — Hailey (@mariehaileyy) November 11, 2015

I am terrified ! We just literally walked passed a racist cult in speakers circle i dont feel safe at Mizzou anymore im ready to go — Hailey (@mariehaileyy) November 11, 2015

There is a blue truck with white guys and there is no license plate on the truck they are circling around us — Hailey (@mariehaileyy) November 11, 2015

Im shaking and crying these white guys are in a monster blue pick up truck no license plate circling our car we almost couldnt get out — Hailey (@mariehaileyy) November 11, 2015

This truck seen driving around #Mizzou campus w/ driver screaming racial slurs at students. #ConcernedStudent1950 pic.twitter.com/vbTjhPXfe1 — D (@Delo_Taylor) November 11, 2015

There university dismissed all accounts as rumors.

There is no immediate threat to campus. Please do not spread rumors and follow @MUAlert at https://t.co/6BXzIBsDxU for updates. — MU Alert (@MUalert) November 11, 2015

Black students began to contact professors to inform them of the current campus climate and their apprehensiveness of returning to campus in light of the recent threats and incidences. One professor, Dr. Dale E. Brigham, replied back to a student saying, “If you don’t feel safe coming to class, then don’t come to class. I will be there, and there will be an exam administered in our class.”

My professor clearly doesn’t care. He still expects me to go to class for an exam while THREATS ARE BEING MADE! pic.twitter.com/R2JO6D723w — killa² (@_youlovejas) November 11, 2015

The campus police department said it was continuing to investigate the threats.