Dean Wasiolek did notify her immediate supervisor, VP for Student Affairs, Larry Moneta, and those initial rounds of communications reached EVP, Tallman Trask, but the Duke Allegations report said that President Brodhead was not contacted until much later. Brodhead first learned of the incident on March 20 from an article in The Duke Chronicle (the student paper).
By the way if anyone wants some interesting reading concerning this case, go to the Chronicle archives starting with the March 20 paper.