The Central Intelligence Agency in 2004 hired outside contractors from the private security contractor Blackwater USA [now Xe] as part of a secret program to locate and assassinate top operatives of Al Qaeda, according to current and former government officials. Executives from Blackwater, which has generated controversy because of its aggressive tactics in Iraq, helped the spy agency with planning, training and surveillance... It is unclear whether the C.I.A. had planned to use the contractors to actually capture or kill Qaeda operatives, or just to help with training and surveillance in the program... But government officials said that bringing outsiders into a program with lethal authority raised deep concerns about accountability in covert operations... Officials said the C.I.A. did not have a formal contract with Blackwater for this program but instead had individual agreements with top company officials, including the founder, Erik D. Prince... Blackwater’s work on the program actually ended years before Mr. Panetta took over... A Xe spokeswoman did not return calls seeking comment.