The ongoing criminal investigation into three Michigan State football players and an alleged sexual assault now involves a fourth person from the university.

Scott Hughes, a spokesman for the Ingham County Prosecutor’s Office, said Friday morning there was one other warrant request involving a Michigan State University staff member along with the three sexual assault warrant requests.

“The fourth one is a non-sexual crime alleged, I believe an obstructing an investigation and then maybe an MSU ordinance violation,” Hughes said.

University spokesman Jason Cody confirmed Tuesday that Curtis Blackwell, the football program’s director of college advancement and performance, has been suspended with pay. The university could not release details or circumstances surrounding the suspension.

Related: MSU football staffer Curtis Blackwell suspended

Cody had confirmed Monday that an unidentified football staff member was suspended on Feb. 9, pending the completion of a Title IX investigation. The university would not confirm that Blackwell is that staff member.

Ingham County Prosecutor Carol Siemon on Thursday afternoon said she has asked Michigan State University Police to continue their investigation and “submit to our office additional information and evidence.” Siemon said in a release that she would then review those materials and determine what and if charges will be filed. MSU Police submitted their initial report Thursday morning.

The report of a fourth warrant request was initially reported by's Dan Murphy.

The three unidentified players who are under investigation are suspended from football activities and have been removed from university housing. The alleged sexual assault took place in “late January,” according to MSU. No other details have been released.

Related: Suspended MSU football players still on scholarship

Cody said Monday the three players “were suspended as soon as allegations naming them were made to the Athletics Department leadership,” but declined to discuss the specifics of the suspensions or their timing due to the ongoing and separate criminal and Title IX investigations. All three players remain on their athletic scholarships. Cody said because they have been removed from on-campus housing, they are receiving a prorated stipend to live off campus, per federal cost of attendance rules.

MSU has outsourced the Title IX investigation to Ann Arbor-based Rebecca Veidlinger, who previously had served as head of MSU’s Office for Institutional Equity and interim Deputy Title IX Coordinator. Veidlinger is in her final year of a three-year appointment to the State Bar of Michigan Domestic Violence Committee. She told the Free Press via email Monday that she cannot comment on the Title IX investigation or offer a timeline for its conclusion.