The Carlyle Group, one of the world’s largest private equity funds, may soon acquire the $2 billion government contracting business of consulting giant Booz Allen Hamilton, one of the biggest suppliers of technology and personnel to the U.S. government’s spy agencies. Carlyle manages more than $75 billion in assets and has bought and sold a long string of military contractors since the early 1990s. But in recent years it has significantly reduced its investments in that industry. If it goes ahead with the widely reported plan to buy Booz Allen, it will re-emerge as the owner of one of America’s largest private intelligence armies.