SPRINGFIELD, Mo. -- Missouri State University's top black official announced his resignation Monday, less than a week after the school said an investigation by outside attorneys found "no credible evidence" the university discriminated against him.

The school released a statement saying Ken Coopwood, vice president of diversity and inclusion since October 2011, will be on leave until his resignation takes effect April 30. Coopwood, the school's first black vice president, said in the statement he thought it best to pursue opportunities outside the school.

"There are many people at the university and throughout Springfield who are committed to ensuring that the Missouri State campus is known for being a place of inclusion, and I am confident that the good work will continue on campus and in the community after my departure," Coopwood said.

The Missouri State Board of Governors hired three Springfield attorneys in December to investigate after an online petition alleged Coopwood was subjected to "despicable and hostile" behavior by his staff. His supporters also alleged the school administration discriminated against Coopwood and marginalized him by restructuring his job a year ago.

Stephen Hoven, chairman of the Board of Governors, said investigators interviewed 38 people, including 12 suggested by Coopwood, and reviewed dozens of documents including employee emails, Coopwood's personnel file, student demand lists and employee complaints.

The Springfield News- Leader reported investigators said the report showed the restructuring of Coopwood's job -- and other changes -- were due in part to "ongoing complaints by personnel within the division for Diversity and Inclusion."

Citing privacy considerations, the university did not release the full report. It has refused to detail the complaints. But in a summary released last week, investigators wrote, "Based upon our investigation, we find no credible evidence which leads us to conclude that Dr. Coopwood has been discriminated against because of his race in connection to his employment at the university."

"I agreed to the investigation and actively participated in it," Coopwood said in the statement released Monday. "I think that the investigation team took the matter seriously and conducted a thorough investigation. While I accept the investigation and its findings, I have decided that it would be best for me to pursue other professional opportunities."

University President Clif Smart said he, Coopwood and the Board of Governors agreed the resignation was necessary.

"It was a mutual decision that it was going to be a challenge moving forward," Smart said.

Springfield business owner DuSean Howard, a friend of Coopwood's who started the petition, said Monday after hearing about the resignation, "My fear has come to pass, but I can't say that I am surprised by the news."

The university plans a national search for Coopwood's replacement. Smart said the position will be evaluated to see if any changes need to be made, but the university believes having a top official working on increasing diversity and inclusion is important and the job will remain a level of high importance.