A top executive of a defunct real estate investment company has admitted to running a Ponzi scheme that duped investors out of $658 million. Thomas Nicholas Salzano, 65, of Secaucus, pleaded guilty in Newark federal court on Tuesday to securities fraud, conspiracy to commit wire fraud and conspiracy to defraud the United States, the U.S. Attorney’s Office District of New Jersey said. As part of his plea, he admitted that he made misrepresentations to investors while working behind the scenes at National Realty Investment Advisors and used millions of dollars of investor money on personal expen…