Video (01:55) : Students at a Monday morning sit-in said racism is "embedded'' on the campus of the Northfield college.

– Infuriated by racist graffiti and threats on campus, St. Olaf College students boycotted class Monday and called for sweeping changes at their school.

After a day of tears, impassioned speeches and hours of negotiations between students and the administration, St. Olaf President David R. Anderson signed off on student demands to address their concerns about flagrant racism on campus.

"I no longer feel safe, no longer feel welcome," said Don Williams, a St. Olaf junior who returned home from walking his dog last week to find a note, scrawled with a vile racial slur, tucked onto his car windshield.

Williams told the hundreds of students rallied around him Monday in the campus administration building about the shock of seeing a word that had already been sprayed as graffiti around campus now targeting him where he lives in town.

"The only thing I could think was ... what can I do to stop this from happening to the next person?" he said.

On the heels of that threatening note came another, tucked into a student's backpack, then a third, late last week, left on senior Samantha Wells' windshield, with another racial epithet and a threat: "Shut up or I will shut you up."

Gallery: St. Olaf students boycott Gallery: St. Olaf students boycott

The notes followed a spate of racist graffiti incidents stretching back at least to last fall. The campus erupted into protests and organizers spent a sleepless weekend drafting a lengthy list of demands for the administration, ranging from improved racial and cultural sensitivity training on campus to the removal of a campus advisory board member they consider a "Christian Zionist."

The college responded to the student uproar by canceling classes Monday and organizing a morning forum between students and Anderson, just down the hall from the atrium where student activists were rallying to discuss acts the school described as "despicable" and a violation of "every value we hold as a community."

As Anderson's forum began, members of the student group the Collective for Change on the Hill, headed down the hall with an 11-page list of demands and interrupted the forum, asking the president to sign off on the document. Anderson balked at the initial list of demands and the way it was presented to him, but eventually signed off on a revised version that was worked out in front of an auditorium of at least 500 students, with hundreds more listening in over loudspeakers, campus radio and social media.

"The demands reflect a whole set of concerns that students have about their experience at the college and the environment it provides. Let's get them named, let's talk about how they can be addressed," Anderson said. "Let's find a way to move forward together."

The racist graffiti and threats were jarring on a close-knit campus of 3,000, where white students outnumber minorities 4-1 and where it is likely that someone knows the identity of the poison pen writer.

"I'm feeling scared at St. Olaf," said Wells, the most recent recipient of an anonymous threat, fighting tears. "I can't turn a corner without feeling like someone is going to be there, waiting for me. But I'm so thankful for everybody here who's supported me."

Students began arriving at the campus administration building just after 7 a.m. Monday, lugging pillows and blankets, snacks and bottled water, determined to stay as long as needed. For hours, they listened and talked, crowded into the auditorium, hallways, classrooms and atrium of Tomson Hall.

"I want to leave this institution better for people who look like me, than [it was] when I was here," said junior Krysta Wetzel, who is black.

The agreement signed between Anderson and the students includes a pledge to set up an autonomous task force to examine the issues students raised Monday.

"This is an important first step in a process for a long-term solution," the administration said in a statement Monday afternoon. "College leaders are committed to moving forward in a spirit of collaboration with students, faculty, and staff."

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.

Paul Walsh contributed to this report.