Federal agents say they have dismantled the largest mortgage-fraud conspiracy in state history by indicting seven people on charges they bilked banks and other financial institutions out of $48 million, pocketing more than $9 million to fund lavish lifestyles that included matching Lamborghini sports cars. A grand jury issued a 40-count indictment naming two Bellevue mortgage brokers, an Eastside escrow company and an Issaquah real-estate agent in a scheme involving the repeated purchase and resale of Eastside and Seattle-area homes using a succession of paid “straw buyers” or other unqualified borrowers to obtain ever-larger loans they could never pay back, then siphoning money off escrow.