(CNN) For 30 years, a large painting of a hunched Russian czar leaving the Kremlin on horseback hung in David Tracy's home.

Standing over seven feet tall and over eight feet wide, the canvas came into his possession when it was included with a house he bought in Ridgefield, Connecticut, in 1987. But when it came time for him and his wife, Gabby, to retire to Maine, they decided to sell the beloved artwork. Little did they know the attempted sale would lead to a meeting with the FBI, a cease-and-desist letter, and an exchange of cultural justice with Ukraine.

The oil painting they planned to auction off turned out to be an original 1911 painting by Mikhail Panin, titled "Secret Departure of Ivan the Terrible Before the Oprichina," that disappeared from the Dnepropetrovsk Art Museum in Ukraine during World War II, according to a press release from the US Attorney's Office in Washington. It depicts the former Russian ruler and his loyal followers secretly leaving the Kremlin for another Russian city.

The Tracys were notified after the Dnepropetrovsk Art Museum contacted the Washington-based auction house they hired to facilitate the sale. They were asked to immediately stop the auction because the painting was stolen property.

"It was a big shock. At first I thought it wasn't necessarily true," Gabby Tracy, 84, told CNN Monday.

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