ANN ARBOR, Mich. (AP) — The University of Michigan and embattled athletic director Warde Manuel have agreed to a buyout of the remaining years on his contract and he will step down at the end of the year, culminating a decade-long run with four national championships and a string of scandals.The school said Monday the decision was tied to investigations into former football coach Sherrone Moore’s relationship with his executive assistant and a probe into the athletic department’s culture.Manuel led a department behind this year’s men’s basketball title and a football program that won the 2023 national championship, but that wasn’t enough for him to keep his job.Manuel fired Moore following a law firm’s investigation into a relationship he had with a subordinate, and the school later chose to widen the look into the department; a law firm was paid about $12 million to do the work.Manuel previously spoke to Moore and the woman about their relationship, both denied it was inappropriate and he went through their school-issued cellphones and email accounts unable to find anything that would allow him to fire Moore for cause, people familiar with the situation previously told The Associated Press.