An alleged cache of Civil War gold buried somewhere in Pennsylvania caused many to catch a serious case of gold fever. But its location remains unknown, even after an FBI search, writes Jason Nark for The Philadelphia Inquirer.

In March 2018, the Philadelphia FBI spent several days digging for gold in Dents Run, located in Elk County, 200 miles west of Scranton. Post-search, the FBI said it found nothing; however, many treasure hunters believed the agency was lying.

Now, a recently unsealed document shows the FBI thoroughly completed its homework on the case.

The legend of the Elk County treasure dates back to 1863, when a Union detachment transported more than two dozen 50-pound gold bars from West Virginia to Philadelphia. Thieves ambushed the shipment and buried the gold.

In 2018, Agent Jacob Archer of the FBI’s art crime team consulted with treasure hunters and other experts on Civil War gold regarding the treasure. He also sifted through the U.S. Mint and other national archives, seeking confirmation that the story was true and more precise information on a possible burial spot.

Before digging, the FBI scanned the area.

In the end, however, the dig turned up empty.

Read more about the case in The Philadelphia Inquirer.