A San Francisco prosecutor filed a $10-million libel suit against Assembly Speaker Willie Brown, accusing Brown of falsely accusing him of leaking secret grand jury information. Assistant Dist. Atty. John Carbone's suit cited newspaper reports that Brown said Carbone was the source of information leaks during an investigation of Brown's tailor, Wilkes Bashford, who pleaded no contest to a felony theft charge and agreed to pay the city $750,000 back rent. "The quotes accuse me of being a leak of grand jury information," said Carbone, 38. "Such leaking is unethical and it may be a crime as well." The suit seeks more than $5 million general damages and $5 million punitive damages. Brown has referred to Bashford as a close friend as well as his personal tailor.