For months, prosecutors have been investigating allegations that a former county appraiser lowered tax bills for wealthy Westside property owners in a bid to drum up campaign cash for his boss, Los Angeles County Assessor John Noguez. Now, that corruption probe has expanded to include tax reductions allegedly made by the appraiser long before Noguez was elected assessor in November 2010. In fact, the appraiser, Scott Schenter, is suspected of engineering improper tax breaks for nearly a decade, according to documents obtained by The Times and interviews with former co-workers. Retired assessor's office supervisor Dale Edgington said he warned several...