Revealed in pictures at last: How might of US Army responded to Viet Cong sniper

What would you do if you were a 22-year-old soldier, nine months into a tour of duty fighting for the US in Vietnam, and every night you didn't know if a sniper was going to shoot you in your bed?

For James Speed Hensinger, the answer was to get out his camera.

In April 1970, the compound of the 173rd Airborne Brigade had been receiving sporadic night-time visits from a lone Viet Cong gunman, firing down on the soldiers in their huts with an automatic AK47 rifle.

After a while, James explains: "We were pissed off. We decided to use a 'heavy' response the next time the sniper hit us."

The next night, James set himself up in a guard tower near the perimeter of the camp. Using a 35mm Nikon FTN camera, a camera release and some sand bags for a tripod, he waited.

Sure enough, when darkness fell the lone sniper opened fire. And the US army unleashed hell.

From the left and right, two 7.62mm M60 machine guns peppered the hills with rounds, shooting one red tracer for every four normal bullets.

Down in front of James an M42 Duster open turret tank fired its twin 40mm anti-aircraft guns, with its huge white tracers followed by large explosions.

Finally, this was all supplemented by high explosive shells shot from an M2 Browning .50 caliber machine gun, creating white bursts without tracers.

Using long exposures between 15 seconds and one minute, James was able to capture the action with some breath-taking photographs.

He had no idea what they would look like when he mailed them home to be developed, and was amazed when he returned from his 12-month tour to find he had brilliantly recorded the power and force of the American response.

James had kept the pictures to himself until now, choosing to release them to the public in celebration of this year's Memorial Day in the US.

And though the 66-year-old from Westminster, Colorado remained an enthusiastic photographer, he has never been a professional, instead going on from the army to careers as a petroleum geologist, Volkswagen mechanic, university librarian, software developer, published author, IT manager, and corporate manager.

And did they ever catch the Viet Cong sniper?

"We sent out patrols during the day," James says, "and found a blood trail one morning. Otherwise, we never found him.

"The rocks on the slope were as big as Volkswagens. It took a very stupid officer to put a pin in the map and say, "Build it [the camp] here."