Mexican-born American spy who was the first officer of the Central Intelligence Agency (CIA) to be killed in the line of duty. He worked as a cryptographer and a lieutenant colonel for the United States Army Air Forces.
He was posted to China as an Air Force meteorologist during World War II. By 1947, he had quit the Air Force and was employed as a Paramilitary Officer in Special Activities Division (renamed Special Activities Center in 2016) by the CIA. As a cover for that work, he was assigned the position of Vice-Consul for the US State Department at its consulate in Ürümqi (Tihwa), in the Second East Turkestan Republic.
On 29 April 1950 Mackiernan was shot dead by Tibetan border guards after crossing the Chang Tang of Tibet. The US government had failed to request permission, in a timely fashion, from the Tibetan government, and Tibetan messengers had not reached all border guards for the Mackiernan party to enter Tibet unharmed. With imminent threat of the Chinese invasion, Tibetan guards had standing orders in the tense spring of 1950 to shoot all foreigners who attempted to enter Tibet. Furthermore, Mackiernan and his party were dressed as Kazakhs; the Kazakhs in China and the Tibetans were traditional enemies and raided each other across the border.
Mackiernan’s death, as a State Department official, was subsequently reported by The New York Times on 29 July 1950. His work as a CIA agent was first written about in a chapter of a book by Ted Gup, in 2001. However, it was not until 2003 that the journalist Thomas Laird published a book on Mackiernan’s work, which revealed Mackiernan’s atomic intelligence. Later in 2006, Mackiernan’s CIA employment was acknowledged by the CIA, when his name was revealed in the CIA’s Book of Honor. However, his work as an agent, and his atomic intelligence, was not fully recognized by the CIA until then-CIA Director Michael Hayden officially and publicly described Mackiernan’s work during a speech in October 2008.
Link to Wikipedia biography