Robert Toss testified that in 2008, following a business dispute with O'Neal, he falsely told him he had a sex tape.
Ross claimed that two weeks later, he was attacked by gang members who mentioned O'Neal.
O'Neal denied involvement and wasn't charged.
Prosecutors believe Ross was attacked, but his credibility as a witness was undermined by some of his own testimony and behavior.
The Associated Press contributed to this report.
