St. Olaf College said Tuesday that it is scrutinizing “persons of interest” who might be responsible for a string of anonymous racist messages targeting black students.

Carl Crosby Lehmann, vice president and general counsel for the private school in Northfield said that some of the people “of interest” are affiliated with the college and others who are not.

Lehmann added that he has reached out to the FBI, which is working through the Northfield Police Department.

As part of the college’s own investigation, it has “retained a computer forensic consultant who is analyzing evidence relating to one of the recent incidents,” school spokeswoman Kari VanDerVeen said Tuesday.

Jeffrey Van Nest, spokesman for the FBI in the Twin Cities, said that his agency “has been in touch” with police, and “we stand by ready to assist as requested.”

Northfield Police Chief Monte Nelson said his department has initiated investigations in two of the incidents. Nelson said one has been closed “at the victim’s request” without charges, while another remains active.

Students packed into the campus’ Buntrock Commons on April 29, soon after a black student found a typed note on her vehicle that used the N-word and threatened to harm her.

In late April, St. Olaf President David R. Anderson expressed his anger about the numerous racist expressions that have persisted on the largely white campus since last fall. He likened the acts to a form of terrorism.

Amid threat of a class boycott, St. Olaf called off classes on May 1 for the roughly 3,000 students, and Anderson signed off on student demands to address their concerns about the incidents.