The Federal Bureau of Investigation investigated Brown when he was Speaker. One investigation was a sting operation concerning a fake fish company attempting to bribe Brown; he was not charged with a crime. The FBI further investigated Brown from 1998 to 2003 over his appointees at the Airport Commission for potential conflicts of interests. Brown friend, contributor, and former law client Charlie Walker was given a share of city contracts. Walker had previously thrown several parties for Brown and was among his biggest fundraisers. He had served jail time in 1984 for violating laws concerning minority contracting. The FBI investigated Walker. The FBI also investigated Brown's approval of expansion of Sutro Tower and SFO. Scott Company, with one prominent Brown backer, was accused of using a phony minority front company to secure an airport construction project. Robert Nurisso was sentenced to house arrest. During Brown's administration, there were two convictions of city officials tied to Brown. Brown reassigned Parking and Traffic chief Bill Maher to an airport job when his critics claimed Maher should have been fired. Brown also put his former girlfriend Wendy Linka on the city payroll.