On Dec. 12, 1971, four days before he turned 21, James M. Coon died when the plane he was riding in crashed or exploded during a flight from the Philippines to Tan Son Nhut air base in Vietnam.

Losing a family member in the Vietnam War was hard enough, but the death of Coon, who was from Van Wert, Ohio, was especially trying for his family. They were told little about the circumstances of his death, only that he was declared missing Dec. 12 and presumed dead Dec. 14, 1971.

His body was never recovered.

When the Vietnam Veterans Memorial was dedicated in 1982, the remaining members of Coon’s family were shocked to learn his name wasn’t included among the service members who died in the war.

For decades now, Coon’s family – his mother died in 1976 and his father died around 1982 – have fought to have his name added to the wall, only to be told by military officials and politicians that they can’t help.

Coon’s twin sister, Jan Valentine of Van Wert, says she’s been given various excuses. One was that her brother was just a passenger on a plane that crashed. She’s also been told that he was killed outside a combat zone.

Finally, she says, the family was told that his activity at the time of his death was classified.

In a letter the Navy sent to Sen. Howard Metzenbaum of Ohio in 1992, the Navy said he didn’t meet the criteria to be on the wall. The letter was not signed.

I spoke to the Vietnam Veterans Memorial Fund, which created the Vietnam wall, and they explained that to be on the wall, a person had to die in a combat role in certain geographic areas. Without supporting documents detailing the nature of Coon’s mission, it would be hard to justify putting his name on the wall.

Coon’s story, though, and the story of the nine other men who died with him, is a curious one, his family says, one that almost no one else in America knows.

Though Coon was in the Navy, he also played another role in the Far East. He was a cryptologist with the secretive National Security Agency, responsible for sending and receiving coded messages in war zones.

Valentine says her brother was actually on a ship on his way home when he was given a special assignment. He flew from the ship to the Philippines, then boarded a plane with 10 men, including several cryptologists, for Vietnam. Valentine said all of the men had been requested for the mission, whatever it was.

Last December, though, Valentine received a curious call. It was from someone in the Navy wanting to know whether she was Coon’s twin sister.

She was later invited to a special ceremony Aug. 30 at Fort Meade, Md., where she learned for the first time that the NSA had built a memorial to NSA personnel who had died “serving in silence” in the line of duty.

Among the names on the memorial were six of the men on her brother’s flight, including James M. Coon.

Valentine says she is grateful that her brother’s death was finally acknowledged, but she was again surprised to learn that her brother’s name had been on the memorial since the 1990s, but no one in her family had ever been told about it until now.

None of it makes sense to Valentine. If those men met the NSA’s requirements to be on its memorial, which is a much more exclusive group, if they died in the line of duty, why don’t they qualify for the Vietnam memorial wall?

They were on an assignment that was to bring them into a war zone, she says. They were regarded as on assignment headed for Vietnam as soon as they got onto the plane that crashed.

“When I got back from Fort Meade, I decided I had been quiet long enough,” Valentine said.

Valentine believes all 10 men on the plane that crashed or exploded, not just her brother or the six NSA personnel, deserve to have their names on the Vietnam memorial wall.

“I don’t want it to die here,” Valentine said. “I want the public to know; these 10 men need help.”