The Internal Revenue Service's "Operation Stolen Treasures" revolved around Old Quest Foundation Inc. in Fontana, and De la Fuente and Ramirez and Associates in Rancho Cucamonga, two companies allegedly used to file fraudulent federal income tax returns, a U.S. Justice Department release said.
All but one of the 19 defendants named in the Old Quest indictment are charged with conspiracy to defraud the United States in 421 overt acts.
Three of those charged were the co-owners of Old Quest: Arturo S. Ruiz, who served as chief executive officer; Francisco J. Mendoza, the president; and Francisco Medoza's wife, Maria de Jesus Mendoza, the vice president.
Several Old Quest customers were also arrested.
The indictment against De la Fuente and Ramirez and Associates names four people charged with conspiracy to defraud the United States by filing more than 35 false tax return claims.
Most of the defendants face charges of conspiracy and/or making false claims against the United States.
Notable deaths of 2014 [PHOTOS]