The 1970 painting, Tres Personajes (Three People), by Mexican artist Rufino Tamayo had been left lying in the trash. (Sotheby's/Associated Press)

New York writer Elizabeth Gibson was walking about half a block from her Manhattan apartment four years ago when she came upon a piece of trash that would prove to be treasure.

It was a painting — and not just any painting.The workwas by Mexican artist Rufino Tamayoand had been stolen in 1987.

But Gibson didn't know that.

"When I saw it, I kind of knew it was something. It was just sitting in the trash on the curb," she told CBC News on Tuesday.

"I had my coffee and I came back and said, 'Oh my gosh. I don't understand modern art. I don't have the right apartment for it. There's no reason on earth for me to take what is quote "trash," but I can't leave it here.' "

Something about the painting pulled her in, Gibson said, and she took it home and put it on a wall.

"It is huge and it's very brilliant coloured, very abstract, but you can make out three figures and it's just very powerful, it's overwhelming," she said.

The1970 painting is titled Tres Personajes and other works by its painter, Tamayo,have soared in value in recent years.

AfterGibson made her trash find four years ago, she attempted to discover where the painting came from.

She talked to the doorman of the building where she found it, she talked to friends in the art world, she called a local gallery and told them about the signature on the work and got nowhere.

"It was disturbing in the sense that I didn't understand why I had taken it and I didn't understand" the painting itself, Gibson said.

"It was saying, 'I'm not meant to be here in your apartment, but I'm meant to be someplace. What are you going to do about me?' "

Then she found a familiar image in a book on Tamayo she foundin the library.

"That painting looks very similar to mine. Then I say, 'Oh my god, it's my painting,' " she said. "It's the cover of the book."

She redoubled her efforts to find out more about the work, scouring the internet until she found an episode of Antiques Road Show devoted to missing works of art.

It mentioned Tres Personajes, so Gibson got on a bus to Baltimore — where, she learned, the Antiques Road Show episode was to be rebroadcast —and sherented a hotel room so she could watch.

It turned out the painting had been stolen in 1987 from a Texas warehouse where the owners had placed it while they renovated.

It was owned by a Houston couple, who originally bought it for $55,000 US, and the FBI had investigated the theft.

Information on the missing painting was also available on the databases of the International Foundation for Art Research and the Art Loss Register.

Back in New York, Gibson contacted Sotheby's auction house,and then things began to happen quickly.

A senior vice-president at Sotheby's met with her the next day and came back toher apartment to see the work. Sotheby's had no trouble identifying it as the original Tamayo and contacted the owners, who indicated they wanted to sell.

The work goes up for sale Nov. 20 andthe auction housebelieves it could go for more than $1 million US.

Tamayo, who was born in 1899 in the Mexican state of Oaxaca, initially followed the style of muralists such as Diego Rivera but later developed a more individual style that reflected the vivid colours of Oaxaca. He died in 1991.

Gibson is getting the $15,000 USreward initially offered for return of the painting and an undisclosed "finders fee" from Sotheby's. She said the digging has been an incredible experience.

"I've had a wonderful time with it," she said.