The incident occurred during her semifinal defeat to Kim Clijsters when Williams was called for a foot fault to give the Belgian mum match point and her profanity-laced tirade resulted in a penalty point that ended the match.
Accounts of deep staff divisions and raging internal turmoil became a staple of Clinton campaign coverage, and competing staff leaks and stories of profanity-laced tirades between senior advisers contributed to the impression of a campaign spiraling out of control.
The performance will be their first major showcase since front man Billie Joe Armstrong checked himself into rehab seven months ago for what he called a drug- and alcohol relapse that culminated in a profanity-laced rant onstage in Las Vegas.
Koberna is accused of posting on the public account of social networking site Twitter a threat on Wednesday "laced with profanity, mentioned Kent State University by name (and) also mentioned our president by name and concluded with the expression that he was going to shoot up the campus, " said university spokesman Eric Mansfield.