A week ago we heard the unbelievable story of a California couple who stumbled onto an estimated $10 million worth of gold buried on their rural property. The 1,427 coins were dated from 1847 to 1894 and contained in six steel cans.

Most of the coins had never been circulated and are in mint condition, leading some to speculate that they were stolen.

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The San Francisco Chronicle has highlighted a news story from the turn of the century, which says that a total of $30,000 worth of gold had been stolen from the San Francisco Mint. The coins discovered by the couple had a face value of $27,000.

Also in the report, a historian highlights the existence of one coin in particular that he believes gives credence to the theft theory.

New information, which adds credibility that the heist was an inside job at the Mint, became available late Monday afternoon from research by historian Jack Trout: An 1866 Liberty $20 gold piece — which did not include the words “In God We Trust” — was part of the haul, a coin that alone is worth more than $1 million.

“This was someone’s private coin, created by the mint manager or someone with access to the inner workings of the Old Granite Lady (San Francisco Mint),” Trout said. “It was likely created in revenge for the assassination of Lincoln the previous year (April 14, 1865). I don’t believe that coin ever left The Mint until the robbery. For it to show up as part of the treasure find links it directly to that inside job at the turn of the century at the San Francisco Mint.”

The largest previous find of gold coins in the U.S. was believed to be worth $1 million, found in 1985 by construction  workers in Tennessee.

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For now, it remains just a theory and the San Francisco Mint says it has no information linking the theft to the coin discovery.

The couple already faces a mammoth tax bill after they sell the gold coins, owing about half of the $10 million in proceeds to Uncle Sam and the state of California.

Legal experts Lis Wiehl and Brian Claypool discussed what would happen to the coins if they are found to have been stolen. Both agreed that it seems unlikely that the gold was taken from the Mint because of the dates on the coins.

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