THEY SERVED IN SILENCE

The Story of a Cryptologic Hero

1Lt John F. Cochrane

Dear Folks: Three years ago today on the 15th of October, 1963, your son 

took upon himself a helpmate. This was one of the smartest things I’ve 

ever done. Two years ago today I was in OCS sweating and straining for 

a commission in this man’s Army. Last year I was in Panama sleeping 

in the jungle and playing games. This 15th of October, I am sorry to say 

I am still in the jungle, but this time the jungle of Viet Nam, and they 

are not playing games....I know why I am here and why I couldn’t be 

any other place. The reason is because I believe that principle, basic 

principles are enough for a man to die for”

 1Lt. John F. Cochrane in a letter home to his wife and parents, October 1966

1Lt. John F. Cochrane was born in city of Dearborn in Wayne County, Michigan on April, 16, 1941. The 

county is one of the many Midwestern jurisdictions named after the famous Revolutionary War hero, Mad 

Anthony Wayne. John attended the local schools, graduating from the county’s Edsel Ford High where he 

played football and ran track. After high school he studied psychology at Taylor University and, in 1963, 

enlisted in the U.S. Army. 

After attending officer candidate school and additional training, he was assigned to the Army Security 

Agency (ASA), the organization that served as the signals intelligence branch of the U.S. Army from 1945 to 

1984. In time he joined the ASA’s 409th Detachment at Ft. Meade, Maryland, and in August 1966, deployed 

with the unit to Vietnam in support of the 11th Armored Cavalry Regiment (ACR). 

The mission of the 409th was to provide tactical support to the 11th ACR by collecting enemy Morse 

and voice communications. The unit’s PRD teams (named for the PRD-1 receivers used to conduct 

direction finding missions against enemy units) played an important strategic role by assisting senior 

leaders in discerning future enemy plans and objectives. As the operations officer for the 409th, John was 

responsible for establishing tactical listening posts in the areas of operation. 

Cochrane not only supported U.S. units in Vietnam, in August 1966 he was a part of an intrepid group of 

ASA soldiers who provided indispensable support to Australian units during the now famous Battle of 

Long Tan. During the engagement, an Australian force of 180 men was confronted by over 2500 battlehardened North Vietnamese and Viet Cong soldiers. Despite the enormous odds, the 

battle was eventually fought to a draw, due in part to the crucial work of both ASA and 

Australian signals intelligence units. Their combined efforts were crucial to the Australians’ 

success and survival during the fighting. For their work during this time, John and a fellow 

soldier were awarded medals by their Australian allies. 
Photographs courtesy of the Kent family

MP 33610

Months later, on October 24, 1966, John left the headquarters area in a jeep with a senior officer and his 

driver to scout out potential listening post sites. It was early in the week, but he was looking forward to 

Sunday when he was scheduled to fly to Hawaii to meet his wife Elaine for six days of much deserved 

R&R. Fate intervened. 

At some point during the trip, the senior officer made the decision to take over the driving duties, 

prompting the enlisted driver to move to the back of the vehicle, and Lt. Cochrane to move up to the 

passenger seat. As the vehicle passed just south of Xuan Loc, an enemy sniper fired two shots. The first 

shattered the vehicle’s oil filter, bringing the vehicle to a standstill. Tragically, the second pierced the 

windshield, killing Lt. Cochrane. 

Shortly before his death, John had written a letter home to his wife. It is worth noting that his thoughts 

not only found their way to her, but eventually to President Lyndon Johnson. Johnson was so impressed 

that he incorporated it in his speech at the White House Christmas tree lighting ceremony in December 

of that year. “We are here because we actually believe that our country is good enough to fight for, and 

even if necessary, die for. All we ask is that some good come out of it...” Johnson then read the reply he 

drafted to Mrs. Cochrane. 

“I have known great and wise men but I wish I had known him because then I would have known the best 

of men...This letter is an extraordinary testament. This was the last letter he wrote... It will live as long as 

men will honor courage and bravery.” 

Cochrane was buried at Arlington National Cemetery on November 2, 1966 and was posthumously 

awarded the Bronze Star, Army Commendation Medal, and the Purple Heart. 

John left behind a loving wife and family and many friends and admirers, but as President Johnson 

noted, he would forever be remembered as someone who epitomized the worthy and noble attributes 

of courage, bravery, and devotion to both his fellow soldiers and our nation.