This X-ray provided by the Kroeller Mueller Museum in Otterlo, Netherlands, Tuesday, March 20, 2012, shows an underlying image of two wrestlers on a painting entitled "Still life with meadow flowers and roses" by Vincent van Gogh. The Kroeller Mueller Museum says new X-ray research has finally put beyond doubt that "Still life with meadow flowers and roses" really is by Van Gogh. It has also uncovered in greater detail an art school study by Van Gogh of two wrestlers concealed on the same canvas and invisible to the naked eye. AP Photo/Kroeller Mueller Museum.

It was, it wasn't, it is: A still life once thought to be by Vincent van Gogh but later downgraded to being the work of an anonymous artist is indeed by the tormented Dutch impressionist himself, researchers announced Tuesday.

The process leading to the confirmation of the painting's authenticity reads like a cold case detective story. A new X-ray technique helped experts re-examine what they already knew about "Still life with meadow flowers and roses" and draw on a growing pool of scholarly Van Gogh research.

"Still life with meadow flowers and roses" by Vincent van Gogh. AP Photo/Kroeller Mueller Museum.

A detailed X-ray of an underlying painting of two wrestlers and knowledge of the painter's period at a Belgian art academy led a team of researchers to conclude that the painting really is by Van Gogh.

The painting is owned by the Kroeller-Mueller Museum in the central Netherlands and was being hung there Tuesday among its other Van Gogh works.

There was no real eureka moment for experts studying the still life, said Louis van Tilborgh, a senior researcher at Amsterdam's Van Gogh Museum who took part in the confirmation process.

"All the pieces just fell into place," he told The Associated Press.

The painting, on a 100 cm-by-80 cm (40x31 inch) canvas, was bought by the Kroeller-Mueller Museum in 1974 as a Van Gogh. The work was thought to come from the artist's period living with his brother Theo in Paris from late 1886.

"But when they hung it (in the museum), doubts crept in" about its authenticity, said Van Tilborgh.

Experts thought the canvas was too large for that period, the depiction of a vase brimming over with flowers and yet more flowers lying on a table in the foreground was too exuberant, too busy. The signature was in an unusual position for Van Gogh — the top right hand corner.

With the doubts piling up, the museum in 2003 decided to attribute the painting to an anonymous artist instead of to Van Gogh.

But the detective work did not end there.

An X-ray taken five years earlier had already revealed an indistinct image of the wrestlers and continued to interest researchers. Now, a new more detailed X-ray has shown the wrestlers in more detail, along with the brush strokes and pigments used. They all pointed back to Van Gogh.

"You can see the wrestlers more clearly and the fact that they are wearing loin cloths," said Van Tilborgh.

Having models pose half-naked was a defining characteristic of the Antwerp academy where Van Gogh studied in early 1886. So was the size of the canvas, the Kroeller-Mueller Museum said.

Vincent wrote to his brother about needing the large canvas, new brushes and paint. Theo helped the penniless artist buy the materials and a week later Van Gogh wrote back that he was delighted with the painting of two wrestlers.

Van Tilborgh said the brush strokes and pigments in the wrestlers painting also corresponded with what experts now know about Van Gogh's work in Antwerp.

The wrestlers also help explain the "uncharacteristic exuberance" of the floral still life, the Kroeller-Mueller Museum statement said: Van Gogh had to cover up all of the old image with his new work.

Copyright 2012 The Associated Press.