Insider recently observed scout snipers going through stalking training at Marine Corps Base Quantico in Virginia.

Before the students entered the field, an instructor demonstrated proper technique.

Not only was everyone unable to find the sniper with various optics at the observation post roughly 1,000 feet from his position, but a dozen Marines, a couple of Army Rangers, and I were unable to find him when he was less than 3 feet away.

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Imagine an enemy you can't see, an invisible hunter as lethal as any of nature's fiercest predators. A concealed sniper is by far one of the deadliest forces on the battlefield.

Insider visited Marine Corps Base Quantico in Virginia recently to observe US military snipers as they practiced hiding in plain sight. Before the training began, an instructor showed everyone how it's done.

Scout Sniper School instructor shows Marines and Army Rangers the tricks of the trade at Marine Corps Base Quantico in Virginia. Ryan Pickrell/Business Insider

A combat veteran who knows well the cost of a mistake, the instructor's execution was exceptional down to the last detail. A dozen Marines, a couple Army Rangers, and I failed to spot this man, even when he was only 3 feet away.