NEW YORK •They knew it was a cool painting.
But Mr Buck Burns and Mr David van Auker had not thought that it was a masterpiece until visitors to their New Mexico furniture and antiques shop began asking about the work that they had bought as part of an estate.
It turned out that it was indeed an important work, a painting by Willem de Kooning.
It was stolen 31 years ago from The University of Arizona Museum of Art and lost until Mr van Auker positioned it in a public place - lying on the floor of their shop in Silver City.
Woman-Ochre - one of a number of abstract expressionist paintings that de Kooning did of women in the 1950s - was stolen the day after Thanksgiving in 1985.
There was no surveillance video, but investigators pieced together a rough narrative of the theft that began with a man and a woman following a staff member into the museum at around 9am.
She distracted the staff member while the man cut the painting from its frame with a sharp blade.
In less than 15 minutes, the two left with the painting.
Mr Burns said that when he first saw the painting, he just thought that it was "cool and unique".
Then visitors began asking if it was a de Kooning.
They looked online, found an article about the still-missing work and compared photos with the painting in their shop.
They immediately decided they had to return it, Mr Burns said.
"For us, it was the equivalent of finding a lost wallet and returning it. It was a no-brainer."
On Aug 3, Mr van Auker phoned the museum. Later, he called the Federal Bureau of Investigation.
"It snowballed very quickly from there," the museum's interim director, Ms Meg Hagyard, said.
"I was expecting a marathon, but instead it was a sprint."
She added that the museum is very confident, based on its analysis, that this work is the original painting.
"The best way I can think to describe it is that it's sort of like Cinderella's glass slipper," she said. "We had the original frame and remnants and we were able to match the painting with that. It fits like a glove with the canvas."
There was also evidence of previous conservation work that had been done.
Yesterday, the painting was slated to be unveiled at a news conference before being sent for restoration.
Ms Hagyard said that although it is in relatively good condition, considering the theft, there is damage to be fixed before it can go back on the walls.
"When we hang it, that will be a moment of celebration," she added.
The University of Arizona Police Department declined to comment on the case and whether there was still any interest in figuring out who might have stolen the de Kooning work.
Mr Burns declined to say what they had paid for the estate.
The museum would not speculate on how much the painting might be worth, but de Kooning's work can be wildly valuable.
A Chicago billionaire was reported to have paid US$300 million (S$408.3 million) for a de Kooning painting, Interchanged, last year.
Another Woman painting sold for about US$137.5 million in 2006.
The Dutch-American abstract expressionist artist died in 1997.
The prize for Mr van Auker's return of the painting?
"We're so excited to take him to dinner and to toast him," Ms Hagyard said.