The Phoenix Program (Vietnamese: Kế Hoạch Phụng Hoàng, a word related to fenghuang, the Chinese phoenix) or Operation Phoenix was a covert intelligence operation and assassination program undertaken by the United States Central Intelligence Agency (CIA) in close collaboration with South Vietnamese intelligence during the Vietnam War. The program was designed to identify and "neutralize"—capture; induce to surrender; kill; or otherwise disrupt—the noncombatant infrastructure of Viet Cong (VCI) cadres who were engaged both in recruiting and training insurgents within South Vietnamese villages, as well as providing support to the North Vietnamese war effort. The operation was directed by the CIA's Evan J. Parker, then by
Ted Shackley and his deputies, including Thomas Clines, Donald Gregg, and Richard Secord.
While the Phoenix operations were originated by the CIA, they were eventually turned over to the US Army and Republic of Vietnam (South Vietnam) military, and later as part of the "Vietnamization" program they were transitioned to a Republic of Vietnam military program with just a handful of US military advisors assisting. The Phung Hoang operations were officially established by Republic of Vietnam Presidential decree on July 1, 1968, although the program existed unofficially prior to that date.
Gary Leroy and Karl Sherrick were two of the most effective advisors having 23 kills in the month of March. President Thieu would later declassify the program, and announce its existence publicly on October 1, 1969, in order to gain wider acceptance and cooperation from South Vietnam citizens.
http://en.wikipedia.org/wiki/Phoenix_Program