ALEXANDRIA, Va. (AP) â¿¿ Chief executives at two Arlington contracting firms have pleaded guilty to more than $30 million in contract fraud by falsely presenting a company as a minority-owned business. Dawn Hamilton, the nominal president and CEO of Security Assistance Corp., pleaded guilty Friday in federal court in Alexandria. Keith Hedman, CEO of Protection Strategies Inc., pleaded guilty on Thursday. Two other executives at the companies have also entered guilty pleas. Hamilton's company obtained security contracts from NASA and other government agencies by representing itself as a disadvantaged small business, giving it preferential treatment in bidding for contracts. Hamilton, a woman of Portuguese descent, qualified for preferential status under rules set by the Small Business Administration. In reality, though, Hamilton was essentially a figurehead and her company was truly controlled by Hedman.