A retired FBI agent has revived interest in an alleged case of stolen Civil War-era gold hidden for over 160 years in Pennsylvania.

'This is a conspiracy theory that keeps me up at night,' confessed retired bureau Special Agent Stewart Fillmore, now a 'true crime' author and podcaster.

A treasure hunter claimed he had found buried gold in 2018 and tipped off the FBI to help recover the treasure, but 'nothing was found' after a three-day investigation.

The treasure, worth $41 million in today's dollars, had been destined for the Philadelphia Mint in 1863, where it would help support the Union's 'enormous cost of conducting the war,' per official US Army War documents.

But the shipment vanished, allegedly stolen by a Confederate secret society, the 'Knights of the Golden Circle,' who were said to have buried the gold in a rural part of Elk County.

The treasure hunter, Dennis Parada, worked with the FBI six years ago, with the agency identifying 'a large mass of some kind at the site underground,' said Fillmore.

'The FBI also used pretty high-tech equipment, determining there was a presence of gold,' he added.

Fillmore's assessment of the mystery is accurate: allegations that FBI officials absconded with any treasure they may have uncovered.

'I don't understand why the site survey shows presence of gold, a large mass under the ground and then they find absolutely nothing,' Fillmore said in a short summary of the mystery to his followers on TikTok. 

Fillmore spent nearly three decades with the bureau before  exploring similar intriguing cases from history for his series Texas Crime Travelers, with one of the latest episodes focusing on the Civil War gold.

The story began in 2018, when Parada used ground penetrating radar to see below the surface in a region of the woods, finding indications that a large mass that he believed was the buried gold.

The treasure hunter sought help from the FBI, due to the potential gold sitting on public land.

The agency commissioned scientific tests, revealing an object with a mass up to nine tons and a density consistent with gold.   

A few days later, the FBI showed up with more than 50 agents and construction equipment to dig 12 feet into the ground. But the dig was a bust, or so it was claimed.

And when the FBI turned over a trove of records from the dig, they were incomplete, the treasure hunter claimed. 

However, a local town official said that she saw lights and heard agents working late at night, while others reported seeing armored vehicles in the town, which has for years fueled the conspiracy theory that the FBI stole the gold.

And Kem Parada, Dennis' son, reported that he was also told to 'stay in his car' for the duration of the dig, preventing him from observing what the FBI was up to.

Anne Weismann, the treasure hunters' attorney, told DailyMail.com in 2023 that it would be unusual for a federal investigation not to be logged meticulously.

'From a forensic perspective, you would think that they would use the time and date stamp,' she said. 'To me, that's a big oversight.'

Weismann also believes the FBI is withholding communications it had with the firm whose scientific testing suggested the presence of gold at the site and prompted it to file an affidavit asking for a warrant to seize goods belonging to the US Treasury.

'They get a Writ of Entry that gives them access to the land. They do a three-day search for this, using an excavator and all kinds of techniques, to try to locate this stuff,' Fillmore shared in the video. 

'Very well documented, I have to say. Very thoroughly documented,' he continued, 'and they found nothing.'

This month, Parada told the the Finders Keepers fans and supporters that 'Our FBI case is still on hold' and he is 'waiting word from the Federal Judge in DC.'

'Then, we will take this case to the Senate,' Parada announced. 

Warren Getler, a former Wall Street Journal reporter who helped Parada identify the site, told the Journal he too had 'come to the unavoidable conclusion that the FBI did take the treasure under cover of darkness.'

The treasure hunter has maintained that the episode smacks of a 'major coverup.'

Weismann said the FBI has only provided the site analysis provided by the surveyor and refuses to acknowledge any subsequent contact.

'They want us to believe that after they found nothing, there was never any follow up with that company,' Weismann said.

Getler said the treasure hunters may never be able to prove the FBI made off with a pot of gold. 

But he added: 'What we can prove is that the FBI did conduct a night excavation, despite their denial.'