USAF – Scan from Dana Bell, Air War over Vietnam, Volume IV. Arms and Armour Press, London, Harrisburg (PA), 1984, ISBN 0853686351, p. 62. Cites U.S. Air Force as source.A USAF Douglas/On Mark A-26A Invader of the 609th Special Operations Squadron near Nakhon Phanom Royal Thai Air Force Base, sometime between 1967 and 1969. The B-26K 64-17645 (ex A-26C 44-35546) was rebuilt by On Mark as a B-26K, and used by the CIA in the Congo from 1964 to December 1966 with tail code ‘RF645’, later ‘FR-645’. In August 1967, following redesignation as A-26A, it arrived in South-East Asia, and on 10 November 1969 was turned over from the USAF to the South Vietnamese Air Force. In March 1975, it was blown up at Nha Trang to prevent it from falling into North Vietnamese hands.