HANNIBAL, Mo. – The hometown of one of America’s most enduring and beloved authors is also the site of a decades-old mystery.

Nearly 55 years ago, two young brothers and their friend gathered shovels and flashlights on a spring afternoon to explore a cave in their hometown of Hannibal, Missouri. The boys shared a sense of adventure, much like the heroes of Mark Twain’s novels – Tom Sawyer and Huck Finn.

The families of Joey and Billy Hoag, 13 and 11 years of age, and 14-year Craig Dowell became worried when the boys failed to come home for dinner that evening. Local panic quickly brought national attention to the tiny river town in northern Missouri.

Theories and rumors emerged in the aftermath of their disappearance, some seeming more likely than others. Were they trapped underground by a cave-in? Had they absconded and left Hannibal without telling anyone? Or were they the victims of a notorious serial killer?

On May 9, 1967, the Hoags and Dowell went searching Murphy’s Cave on the southside of town, which had been exposed by construction for Highway 79. They were allegedly chased away by construction workers. That evening, their parents forbade them from going back.

search for Hannibal's Lost Boys
This file image shows search efforts for three Hannibal boys who were last seen May 10, 1967 near cave openings on Hannibal’s south side. (Courtesy: Hannibal Courier-Post)

The boys made plans to go back to the cave after school the following day. On Wednesday, May 10, the boys left school, changed clothes, and went walking in the direction of Murphy’s Cave yet again. According to various accounts over the years, they were last seen between 4:30 p.m. and 5:15 p.m.

For more than a week, members of the Mark Twain Emergency Squad and the National Speleological Society searched Murphy’s Cave and others subterranean systems for any trace of the boys, due to fears they may have been trapped via a cave-in. The Hannibal mayor even requested the help of the Missouri National Guard.

Hannibal Police checked all departing trains the day the boys left to make sure they weren’t attempting to run away or, worse yet, had been kidnapped. Concerned citizens suggested authorities even search the various islands dotting the Mississippi River.

Psychics and clairvoyants of the day reached out with claims the boys were locked in a train car with oranges. That claim, like so many others, would bear no fruit and the preliminary search would be called off 10 days after the disappearance. By June, other searches ended with no clues as to the boys’ whereabouts.

Joey Hoag, Billy Hoag, and Craig Dowell had simply vanished without a trace.

In 2006, construction crews discovered an entrance to the Murphy’s Cave system while building a new elementary school along Highway 79. Searchers checked the cave but there was no evidence of the trio.

Hannibal's Lover's Leap
This image shows a memorial for the boys, located on Hannibal’s Lover’s Leap, just off Highway 79. (Courtesy: Hannibal Courier-Post)

The case would be the subject of several books and even a true crime-style podcast.

One person, who grew up in Hannibal and knew the Hoags, penned a book alleging psychics believe notorious killer John Wayne Gacy, whose victims include at least 33 boys and young men, murdered the Hoags and Dowell.

The Hoags’ surviving sister has wondered if there was a cover-up involving the construction company, which she said had workers routinely blasting in the area and did not put up signs or caution tape around any of the various cave openings caused by their work.

A plaque and stone monument sits atop the Lover’s Leap park overlooking the Mississippi River to honor the memory of the three boys.