Legend has it that in 1863, just before the outbreak of the Battle of Gettysburg, the Union Army dispatched a wagon train filled with gold that would be used to pay Union soldiers. The wagon train departed from Wheeling, West Virginia, and made it St. Mary’s, Pennsylvania. At some point after that, however, the shipment of gold disappeared.

The story might very well be fictional, a mere rumor that has persisted for generations. But perhaps not. As Christine Hauser reports for the New York Times, FBI representatives were seen earlier this month digging up a site in Dents Run, Pennsylvania, where some locals believe the treasure is buried.

The FBI offered few details about what it was doing in the area. In a statement, the agency said only that it was “conducting a court-authorized excavation” and “nothing was found.” But Bridget McClure of NBC-affiliate WJAC reports that Dennis and Kem Parada, owners of the treasure recovery service Finders Keepers, were present at the excavation.

Dennis Parada has been searching for the Civil War treasure for decades. On the Finders Keepers website , he claims that in 2004 he found a trove of artifacts from the Civil War period at the Dents Run site, including knives, tin cans, animal traps, human and animal bones, and traces of a fire pit. Subsequent investigations with “high powered metal detectors” indicated the presence of “a large metal object 8 feet to 10 feet under the fire pit,” Parada writes. He claims that the lost shipment contained 52 bars of gold, each weighing 50 pounds (others say that the wagon train was carrying just 26 bars), but was unable to dig for the treasure because the Dents Run site sits on state land.

“There's no doubt in my mind it’s down there,” Parada told the Pittsburgh Post-Gazette in 2008. “I'm not going to quit until it's dug up.”

But Parada’s theory about the gold has long been met with skepticism from state officials and local historians. On the Finders Keepers website, Parada posted a 2005 letter from Pennsylvania's Department of Conservation and Natural Resources, which said that analysis of the purported Civil War artifacts at Dents Run revealed the objects to be “hunting camp debris” that dated to the 1880s at the earliest.

“There exists no credible evidence,” the letter reads, “to support any conclusions that a lost Federal gold bullion shipment from the Civil War was ever located on State Forest lands in the vicinity of Dents Run, PA.”

Jim Burke, executive director of the local Mt. Zion Historical Society, tells Brandon Griggs of CNN that he undertook his own search for the lost gold, even hiring a private investigator to comb through government records in Washington, D.C.

"We found no credible evidence that there was ever gold there," he says.

In an interview with Hauser of the Times, however, Burke acknowledges that the FBI’s appearance in Dents Run adds a tantalizing wrinkle to the tale of the missing Civil War treasure.

“There had to be some credible evidence to convince them that there might have been gold there,” he says. “That is just creating a mystery in itself.”