One of Tennessee’s most infamous missing persons case involves a child who vanished in the Great Smoky Mountains National Park more than 50 years ago.

The lessons learned from that search has been studied and developed into a modern day science now used for search and rescue operations.

The hunt for Dennis Martin, 6, remains the largest scale search for a missing person in the Smokies.

“He was definitely there,” said park ranger Dwight McCarter. “But, what happened to him? That’s the question.”

McCarter was involved in the 16-day rescue effort for Martin that started June 14, 1969. “Dennis, it’s hard to figure,” he contemplated.

The Martin Family was camping along the Appalachian Trail for the weekend. The boy’s seventh birthday was six days away.

According to former GSMNP deputy superintendent Clay Jordan, Dennis, his brother, and friends decided to hide, then sneak up on the adults.

They were back country camping at the Spence Field area, when Dennis hid behind a shelter. That was the last time he was seen.

“Just within minutes, literally, his father and other adults started searching for Dennis,” Jordan explained, “With no luck.”

By the time his folks were able to get to a ranger station for help, it was dark and raining past 8 o’clock. That forced the search to be paused until the next morning.

The days following his disappearance more and more people were involved in the search.

“The sheer amount of people, with the army and local volunteers, it was a lot of people,” recalled McCarter.

Around 1,400 volunteers looked for Dennis, including hundreds from the National Guard and Federal Troops. The missing case even peaked the interest of the White House and FBI.

At one point, his family did offer a $5,000 reward. But, investigators said there was no credible indication of an abduction.

McCarter, a young park ranger at the time, said that search helped him develop new skills. “I just piddled along. You know, and take my time with stuff because you could miss some stuff.”

The massive search for Dennis helped develop a new science for search and rescue efforts. “We know looking through today’s lens that just throwing a lot of people out in the woods – in the end – is not the best way to try and find somebody,” said Jordan. “We had a lot of people out in the woods trampling clues.”

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Now, modern day searches typically include far less volunteers and more trained personnel like McCarter, who know what clues to look for, “Maybe they threw a banana peel over there.”

Clues that were missed in the search for Dennis.

Despite no sign of the boy for 16 days, his family scoured the park for years following the mysterious vanishing. “Old man Clyde was out searching for that boy,” McCarter remembered. “We would meet him on the Appalachian Trail, and he’d search and search – one year, two years, four years later he was still searching.”

The boy was last seen wearing a red T-shirt, short green trousers, and low-cut Oxford shoes.

Dennis Martin has never been found.