With the help of an art detective and some journalists, Dutch police say they have cracked the case of the mysterious disappearance of a Brueghel painting from a Polish museum 50 years ago.

"Woman Carrying the Embers", also known as "Woman Moving A Bonfire", painted by Flemish-Dutch master Pieter Brueghel the Younger around 1626, vanished from the National Museum in Gdansk during communist times in 1974.

Its whereabouts sparked rumours - including involvement by the Polish secret service - in a story worthy of a spy novel.

The round painting, measuring just 17 centimetres, disappeared but is now under lock and key at a museum in the Dutch province of Limburg, said Richard Bronswijk of the Dutch police's arts crime unit.

"We are 100 percent sure that it's the same painting that disappeared from the National Museum in Gdansk back in 1974," Bronswijk said.

Polish authorities too confirmed the painting's recovery, saying "we are in constant contact with Dutch authorities, including the Dutch police, regarding the case."

Arthur Brand, a well-known Dutch art detective, said suspicions were raised when journalists from the Dutch arts magazine "Vind" spotted the painting at an exhibition last year.

Billed as "not being seen for the past 40 years", the painting was loaned to the Gouda Museum from a private collection.

"A magazine contributor, John Brozius, did some research and stumbled upon an article on a Polish website with an old black-and-white picture," Brand told AFP.

"The article was about a theft that took place in Gdansk in 1974 in which two artworks were stolen: 'The Crucifixion', a sketch by Anthony van Dyck, and a Brueghel the Younger painting," he said.

"Although the people from 'Vind' were not sure, it looked pretty similar to the Brueghel on display in Gouda," Brand said.

The painting depicts a peasant woman holding tongs with smouldering embers in one hand and a cauldron of water in the other. It appears to refer to an old Dutch proverb: "Never believe a person who carries water in the one hand and fire in the other", or beware of duplicity.

The painting's value is unknown, but Brueghel the Younger's works generally sell for millions of dollars, according to the auction house Christie's.

Brand, nicknamed the "Indiana Jones of the Art World" for his high-profile recoveries of stolen pieces, was called in for help.

With Dutch police, Brand investigated the identity of the painting, which in the meantime had been moved to a museum in Venlo, in the south of the Netherlands.

Brand also scoured Interpol's database, which had an "alert" for the Brueghel painting.

"I concluded that the painting listed by Interpol and the one on display was one and the same," he said. "We have checked and re-checked, including information on the back of the painting. It's a match!" added Bronswijk.

Dutch police have informed Polish authorities, who said Monday they were "taking all possible measures to return the artwork to its original collection."

Once the relevant procedures had been completed, "we will provide information for the transfer of the painting," the Polish culture ministry said.

Asked about the discovery of the Brueghel, Gouda Museum's arts curator Ingmar Reesing said the museum was "very surprised" when it learned about the painting's history.

"But... it's great for the art world that the work has resurfaced after all these decades," he said.

The theft was first discovered on April 24, 1974, when a museum worker accidentally knocked the Brueghel off a wall.

"Instead of the original work by the famous Flemish painter, a reproduction cut out of a magazine fell out of the frame," stolen Polish arts expert Mariusz Pilus wrote in "Arts Sherlock" in 2019.

Days later, a Polish customs officer who had reported the illegal export of artworks through the Baltic port of Gdynia, is said to have been set alight and killed, shortly before he was to be interviewed by police.

Investigations into the death and the paintings' disappearance were shut down shortly after, Polish reports said.

Dutch police are now investigating how the painting ended up in a private Dutch collection.

Brand said he hoped the Brueghel could soon be returned to Gdansk, "to be put on display, in a museum, where it belongs." | AFP