Portrait of a Young Man by Polish painter Krzysztof Lubieniecki (FBI)

Polish baroque painter Krzysztof Lubieniecki finished “Portrait of a Young Man” sometime around 1728, and the work of art eventually made its way to Poland’s National Museum in Warsaw.

Then, like thousands of other European artworks, the painting fell into Nazi hands during World War II. For many years the Lubieniecki painting existed only on lists documenting looted art, accompanied by a black-and-white photo to prove its existence.

Now, decades after its theft, “Portrait of a Young Man” is back with Polish officials, the FBI announced Monday.

Where had the painting been all this time? Mostly in Ohio, according to authorities, and some serendipitous research helped unearth it.

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The Lubieniecki painting has long been thought to have been one of many that the Nazis stole from the Warsaw museum in October 1944 and took to an Austrian palace, the FBI said in a statement. That palace, identified by the Polish embassy as Fischhorn Castle, eventually came to house an Allied Forces battalion.

A small chapel in the castle was “filled with works of art that had been stolen by the Nazis and used as a depository,” according to the Monuments Men Foundation, which honors service members tasked with protecting art and architecture in war-ravaged Europe.

“‘The Portrait of a Young Man’ was apparently later discovered by a U.S. serviceman while in Austria,” the FBI said in a statement. “The soldier is believed to have brought the artwork to the United States after his service abroad.”

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The solider died and the painting was sold to “innocent purchasers” throughout the Columbus, Ohio area, according to the FBI. And there it remained, in Ohio, for many years.

But recently a relative of the U.S. solider came across photos of the artwork while conducting some family research. More research revealed that the painting, once housed in the Warsaw museum, had likely been taken by the Nazis.

The soldier’s relative reached out to Polish authorities and “upon learning of the historic rights of the painting, the possessors agreed to return the work to Poland,” the FBI said.

Officials held a repatriation ceremony in the FBI’s Columbus office.

“We are honored to return this painting to the Polish government and the National Museum,” Special Agent in Charge Angela Byers said in a statement. “This was truly a cooperative effort among the U.S. government and our international partners to ensure this work of art was returned to its homeland.”

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Poland’s Ministry of Culture and National Heritage has a database of more than 63,000 objects lost during WWII. “Several dozen works of art” have been recovered so far, according to the Polish embassy.

Last year, U.S. federal officials returned to Poland “St. Philip baptizing a servant of Queen Kandaki” by German artist Johann Conrad Seekatz. “Stolen art, antiquities, and fraudulently-acquired artifacts, these are the little known casualties of war,” U.S. Special Agent in Charge of Homeland Security Investigations James Hayes said at the time.

“We treat every painting, every sculpture, every historical artifact with utmost importance — they are the missing pieces of a puzzle that make up the Polish national heritage,” then-Polish minister of culture and heritage Bogdan Zdrojewski said in 2014.