You're fighting a losing battle. They won't be able to prove if it was said or not. Most people recognized that from the jump. Let's say those two escorts say "I didn't hear anything" and the UI decides to make a press release saying "Based on our investigation, we have determined that the claim of a racial slur being shouted at Mr. Gomez and company cannot be verified, and hence forth The University of Iowa feels the accuser was acting in bad faith." Do you think that would make us look better, or worse? What amount of evidence do you think they need to "hold him accountable"? Iowa has shown they don't tolerate racism, as well as an overwhelming amount of the fan base who have supported the sentiments of the University and Tom Brands.