St. Olaf College was in upheaval over the weekend as students gathered to protest a string of racist incidents on campus, the latest being a threatening note that was left on the windshield of a black student’s car demanding that she “shut up or I will shut you up.”

Protests are expected to continue with a student boycott of classes on Monday.

David R. Anderson, president of the private liberal arts college in Northfield, acknowledged in an e-mail sent to students on April 21 that there have been numerous racist expressions on campus stretching back to last fall, and he likened them to a form of terrorism.

“I am as angry and frustrated as you are at the repeated ­violations of our values and community norms by someone who defaces the campus with scrawled racial epithets,” Anderson wrote. “I would love nothing more than to discover who is responsible for these acts and to remove that person from our community.”

Students swarmed the interior of the campus’ Buntrock Commons on Saturday night in response to this incident and others. Among them was the woman who found the note on her vehicle that afternoon. It read: “I am so glad that you are leaving soon. One less [N-word] this school has to deal with. You have spoken up too much. You will change nothing. Shut up or I will shut you up.”

Speaking to her fellow students, senior Samantha Wells was quoted by the Northfield News as saying, “It’s been something that’s been going on all year. I think the big message is we shouldn’t let this happen again. The administration needs to do something that stops it indefinitely.”

Student Amanda Vergara, who attended the rally, said, “This is the third time a black student has been individually targeted with an anonymous letter” in the past week.

One student found a note on his car that had “the N-word on it,” she said. “Then on Monday afternoon, a student returned from work and a note was put in her backpack that said, ‘Go back to Africa.’ ”

Vergara said Saturday night’s protest pretty much filled up balconies and the main floor inside Buntrock Commons.

One black student, Krysta Wetzel, got behind a megaphone from high above and said to the protesters and others going about their weekend routine, “We as students of color feel unsafe on this campus, and we will continue to make noise and disrupt your lives until ours are made safer in a really strategic and structured way.”

Wetzel added that on such a small campus, someone needs to step up and reveal who is behind the racist messages. “I think on a campus of 3,000, where you can’t even [pee] alone, someone somewhere knows who it is,” she said.

“Also, if you’re the one,” she continued, “I live in Rand 200. My P.O. box says Krysta Wetzel. If you sign your name, we can have a conversation.”

The pushback resumed Sunday morning at the campus chapel, where “students lined up standing on the sides of the chapel in solidarity” for about 15 minutes before leaving to make plans for further student response, according to Vergara.

On Monday, students will boycott classes and gather in Tomson Hall beginning at 7:50 a.m., Vergara said. Tomson is where the president’s office is located.

School spokeswoman Kari VanDerVeen said college leaders will meet with students Monday morning “to listen and answer questions.”

St. Olaf is the latest campus in Minnesota to confront racist behavior in recent months. In November, a racial epithet was scrawled on a sidewalk at the University of St. Thomas in St. Paul. “This is not who we are and cannot be tolerated,” St. Thomas President Julie Sullivan and Provost Richard Plumb said in a joint statement soon afterward.

In December, the Office for Civil Rights of the U.S. Department of Education said in its 2016 annual report that it received 198 complaints related to racial harassment at colleges and universities nationwide.

Enrollment at mostly white St. Olaf as of last fall was roughly 3,000, with 2 percent identified as black or African-American.

Anderson said in his e-mail that the incidents have a pattern. “Even the handwriting on the notes is similar from incident to incident,” he wrote.

“This person has adopted a strategy similar to the one terrorists use,” the president continued, by acting “under the cover of darkness and anonymity [to] engage in acts that frighten, dishearten and frustrate people with a goal of unsettling the community and turning people against one another.”

The president said that when the incidents began in the fall, he “swiftly informed the community and unequivocally denounced the person and this person’s acts. I have deliberately not repeated my announcement every time this person scrawls another racial epithet somewhere because then this person wins. I don’t want to give this person the power to evoke at will a message to the campus from the president.”

In a news release issued Saturday evening, St. Olaf said officials are doing “everything we can to catch the people involved in perpetrating these hate-filled acts. An active investigation is underway, and there are several leads that we are following up on using every tool we have at our disposal.” Northfield police are assisting in the investigation.