A former executive of Bank of America Corp.’s Countrywide unit testified she wasn’t part of a scheme to defraud Fannie Mae and Freddie Mac by selling them thousands of defective loans, Bloomberg News reported yesterday. The U.S. sued Bank of America in October, joining a whistle-blower action filed by another former Countrywide executive, Edward O’Donnell. The U.S. claims Bank of America and Countrywide, which the Charlotte, N.C.-based bank acquired in 2008, sold thousands of defective loans from 2007 to 2009 to the home-mortgage finance companies. The case is the first brought by the U.S. against a bank over defective mortgages to go to trial. Mairone, the only individual named as a defendant in the case, testified in response to questioning by her lawyer, Marc Mukasey. Mairone said she now works for JPMorgan Chase & Co. Countrywide engaged in the fraud to boost profits, making at least $165 million, Assistant U.S. Attorney Pierre Armand told jurors in his opening statements Sept. 24.