The report says the student alleges former senior associate athletic director John Chadima put his hand down the student's pants at the end of a party in Chadima's suite at a Los Angeles hotel on Dec. 31.
The student - identified only as John Doe in the report - said he was "shocked and frightened" and slapped Chadima's hand away.
Chadima was put on administrative leave on Jan. 6 and resigned the same day. He previously had issued an apology for a "lapse in judgment," and issued another statement through his attorney Tuesday.
"I make no excuses and have come to the realization that over the past few months, alcohol had controlled and consumed my life," Chadima said. "I am taking steps to correct that problem in my life at this time. I will take full responsibility for my lack of judgment and actions that evening."