It's the stuff of legend: A wagon from the Union Army supposedly lost a huge cache of gold bars while en route from Wheeling, West Virginia, to the US Mint in Philadelphia in 1863.

More than 150 years later, the FBI is overseeing a dig in a Pennsylvania state forest where the famous loot might be buried, reports the AP.

The dig is taking place at Dents Run, about 135 miles northeast of Pittsburgh, though no parties involved—the FBI, the state, or the treasure-hunting group Finders Keepers—are saying much.

"I'm sorry, but as of right now all we're allowed to say is 'No Comment,'" a group member tells the Washington Post. "We'll keep you in mind when/if anything changes." Finders Keepers has long insisted that the gold is there, as detailed in this older post on its website, but it says skeptical state officials have never authorized a dig.

That apparently changed last week as the excavation got underway. Various accounts say the Union wagon train was carrying 26 or 52 gold bars, which would be worth $27 million or $55 million, respectively, today.

The Philadelphia Inquirer notes that a Civil War sergeant supposedly claimed that he was the lone survivor of an ambush on the wagon train, and the dig site is about 9 miles from where he said the ambush took place.

Historians have been skeptical about the story over the years, but Finders Keepers says it has found artifacts at the site suggesting Union soldiers were there.

The group also says metal detectors suggest something is buried there. Whether the lost gold is a tall tale or a genuine treasure should be known soon.

(Elsewhere, a fortune in gold might be buried in the Bay Area of California.)

This article originally appeared on Newser: Legendary Lost Gold May Have Been Found