COLUMBIA, Mo. -- A recently-retired senior administrator was appointed Thursday as the interim replacement for the University of Missouri system's president who resigned amid student-led protests over his administration's handling of racial complaints.

The University of Missouri's governing board tapped Michael Middleton, 68, to take over for Tim Wolfe.

Middleton, who is black, resigned as deputy chancellor of the Columbia campus in August and took on the role of deputy chancellor emeritus. He had been working part-time with the campus' chancellor, R. Bowen Loftin, on a plan to increase inclusion and diversity at the school.

Loftin also announced Monday he would be stepping down at the end of the year for a different role at the school. His and Wolfe's resignations came after 30 black members of the football team gave a big boost to the protest movement by vowing not to take part in team activities until Wolfe was gone.

MU Policy Now, a student group made up of graduate and professional students, had been pushing for Middleton's appointment.

"Given the recent turmoil, Deputy Chancellor Emeritus Middleton is a strong transitional figure," the group wrote in a letter of endorsement posted on its Facebook page and sent to curators. Several student organizations signed the recommendation letter, including the Legion of Black Collegians.

Middleton has a bachelor's degree from Missouri and became one of the first black graduates of the law school in 1971. He worked with the federal government in Washington and was a trial attorney in the Department of Justice Civil Rights Division before joining the university law faculty in 1985.

He also helped found the Legion of Black Collegians, a student group involved in the current protest, and himself participated in previous campus protests for civil rights and against the Vietnam War.

He was interim vice provost for minority affairs and faculty development starting in 1997, and a year later was named deputy chancellor.

In that role, he was credited with turning women's studies and black studies programs into their own departments.

Meanwhile, a 19-year-old man accused of posting online threats to shoot blacks on the Columbia campus was expected to appear in court via a video link from jail, where he's being held on bond.

Hunter M. Park, a 19-year-old sophomore at one of the other University of Missouri System campuses in Rolla, is charged with making a terroristic threat, which is punishable by up to seven years in prison.

The threatening posts showed up Tuesday on the anonymous location-based messaging app Yik Yak, and were concerning enough that some classes were cancelled and some Columbia businesses closed for the day.

One of the threats said: "Some of you are alright. Don't go to campus tomorrow" -- a warning campus police Officer Dustin Heckmaster said in a probable cause statement that he recognized as one that appeared ahead of last month's Oregon college shooting involving a gunman who killed nine people and himself.

Heckmaster wrote that Yik Yak willingly gave him the cellphone number that Tuesday's poster had used to create the account from which the threats originated. AT&T later told investigators that the number was Park's and that cellphone towers showed that the postings came from the Rolla area, the officer wrote.

University of Missouri-Columbia police records show the department had contact with Park last January, Heckmaster wrote without elaborating. Those records noted that Park was a student at Missouri University of Science and Technology in Rolla, where Heckmaster confronted Park early Wednesday in the sophomore computer science major's dorm room.

Heckmaster wrote that Park admitted the posts were "inappropriate." He said he asked if the threats amounted to "saber rattling," and Park responded, "pretty much."

When questioned specifically what he meant by the phrase, "Some of you are alright. Don't go to campus tomorrow," Park "smiled and stated, 'I was quoting something,"' Heckmaster wrote. When pressed whether it was mimicking the Oregon shooting's posting, Park replied, "Mmhmm."

When asked why, Park said, "I don't know. I just ... deep interest," Heckmaster wrote.

A message left on Park's mother's cellphone was not returned, and there was no response to knocks on the door of the family's home in the affluent St. Louis suburb of Lake St. Louis.

A second student was arrested at Northwest Missouri State University in Maryville for allegedly posting a threat on Yik Yak that read, "I'm gonna shoot any black people tomorrow, so be ready." Northwest Missouri State spokesman Mark Hornickel told several media outlets that authorities hadn't linked the incident to threats at the University of Missouri's Columbia campus.