Central Michigan University received a resignation letter from William Merrill today.
Merrill is the professor who is the subject of a child pornography investigation.
According to a press release from the University, Merrill's resignation is effective immediately.
Merrill, a tenured faculty member in the College of Education and Human Services, was named last week in a felony complaint from the Isabella County Trial Court, according to the press release.
Merrill had been placed on leave with pay last week, pending an employment investigation. Central Michigan says his resignation concludes that leave.