Tammy Bullock of Boulder, Colorado found a oil painting in the garbage decided to pick up it, held it for 10 years, and fetch it when moving into a new home. she felt it could be worth something  "I just knew it meant something.It was greatly powerful, and even though I didn't realize it. I knew it had good value," she told the Associated Press news agency. 

Information on the painting was posted on the databank of the International Foundation for Art Research
It is still not known how the painting ended up on the street.

The owners - a couple from Houston whose names have not been disclosed - bought the oil on canvas, with marble dust and sand worked into the paint, in 1977 at Sotheby's.

Sotheby's said the painting, which it described as an important work of the artist's mature period, would go up for sale at its Latin American Art auction on 20 November.