LA's Getty and New York's Metropolitan are among the prominent American museums publicly embarrassed recently by revelations of stolen artifacts in their collections. Yesterday, four others were raided by dozens of federal agents in Southern California--with TV news crews notified in advance. It's all part of a five-year investigation into looting, smuggling and income tax fraud. The Los Angeles County Museum of Art, Pasadena's Pacific Asia Museum and Orange County's Bowers Museum are highly respected institutions --or at least they were. Search warrants released after the raids reveal taped phone conversations and other evidence of unethical and possibly illegal practices. Jason Felch, who has helped to expose recent high-profile art scandals in the Los Angeles Times, is co-author of the forthcoming book, Chasing Aphrodite.