SAN DIEGO (AP) â¿¿ Federal prosecutors say they've charged a former San Diego executive in a $28 million stock fraud. Assistant U.S. Attorney Timothy Perry says the indictment charging Mark Anthony Lopez was unsealed Tuesday, accusing the former President and CEO of mining company Unico, Inc. of conspiracy and obstructing justice. Lopez is accused of conspiring with New Jersey-based stock trader Mark Allen Lefkowitz to manipulate the share price of Unico's stock to benefit insiders at the expense of shareholders. Lefkowitz has already pleaded guilty. Lopez is also accused of trying to obstruct the investigation into his misconduct by refusing to turn over emails that were printed and hidden in manila folders marked "Files Deleted" and "Not Released to SEC Subpoena (Delete)." Lopez faces up to 65 years in prison and $750,000 in fines.