Created during World War II as [one of America's most secretive espionage agencies] the Pond existed for 13 years and was shrouded in secrecy for more than 50 years. It used sources that ranged from Nazi officials to Stalinists and, at one point, a French serial killer. It operated under the cover of multinational corporations, including American Express, Chase National Bank and Philips, the Dutch-based electronic giant. One of its top agents was a female American journalist. Now the world can finally get a deeper look at the long-hidden roots of American espionage as tens of thousands of once-secret documents found in locked safes and filing cabinets in a barn near Culpeper, Virginia, in 2001 have ... become public. The papers, which the Pond's leader tried to keep secret long after the organization was dissolved, were placed in the National Archives in College Park, Maryland, in 2008 but only opened to the public in April. Those records plus documents obtained by The Associated Press in the past two years from the FBI, CIA and other agencies under the Freedom of Information Act portray a sophisticated organization obsessed with secrecy that operated a network of 40 chief agents and more than 600 sources in 32 countries. The AP has also interviewed former officials, family members, historians and archivists.