WASHINGTON - William S. Sessions, an FBI chief under three U.S. presidents who won praise for bringing more diversity to the agency but who was fired after being investigated for ethical lapses, died Friday aged 90, U.S. media reported.The cause was complications of a congestive heart ailment, the Washington Post and other media reported, citing his family. He died at his son's home in San Antonio, Texas. Appointed by Ronald Reagan in 1987, and serving under George H.W. Bush and Bill Clinton, Sessions headed the Federal Bureau of Investigation for six years. But he was brought down by ethical lapses including not paying taxes and misusing public funds.Clinton fired him as FBI director in 1993 when he would not resign despite the controversy over those lapses and accusations of weak leadership.A Justice Department report accused him of violations including evading income taxes on the use of his official limousine, using FBI aircraft for personal trips to visit relatives and improperly using government funds to install a $10,000 fence for his residence.Sessions, a former federal judge and prosecutor from Texas, denied any ethical improprieties.Sessions, a longtime Republican who was out of place in the Democratic Clinton administration, was criticized not just over the ethical violations but for the agency's performance and his hands-off management style.During his tenure he sought to open up the FBI to more minorities and women. He helped negotiate a 1992 settlement over a potential lawsuit by black agents charging racism and he resolved a similar discrimination case brought by Hispanic agents."There is no room in our workplace for discrimination -- actual or perceived. Any evidence of bias must be addressed immediately," Sessions told his subordinates in trying to end a lingering legacy from the J. Edgar Hoover era.Sessions was also credited with improving the FBI's rocky relations with Congress -- another problem area that had dated back to scandals when Hoover was director.The Justice Department investigation found insufficient evidence to warrant an independent criminal investigation. But Sessions was ordered to pay back taxes and to reimburse the government for the improperly billed trips.High-profile FBI operations during Sessions' tenure included the disastrous 1993 raid on cult leader David Koresh's compound in Waco, Texas, leading to the deaths of Koresh and about 80 of his followers.