ZURICH, Switzerland - Three gunmen in ski masks and dark clothes burst into a museum just before closing time. After a quick run through the building, they hustled out the door and sped off with paintings by Cezanne, Degas, van Gogh and Monet valued at $163.2 million. Authorities appealed Monday for any witnesses to help reconstruct the robbers' getaway from the E.G. Buehrle Collection, a private museum of Impressionist works whose founder had his own troubled history with stolen art. "This is an entirely new dimension in criminal culture," police spokesman Marco Cortesi said, calling it the largest art robbery in Switzerland's history and one of the biggest ever in Europe. The three robbers entered the museum a half-hour before its scheduled close Sunday. While one trained a pistol on museum personnel ordered to lie on the floor, the two others collected four paintings from the exhibition hall, police said. The men, one of whom spoke German with a Slavic accent, loaded the paintings into a white vehicle parked out front. Police said the paintings may have been sticking out of the trunk as the robbers made their getaway. A reward of $90,000 was offered for information leading to the recovery of the paintings — Claude Monet's "Poppy field at Vetheuil," Edgar Degas' "Ludovic Lepic and his Daughter," Vincent van Gogh's "Blooming Chestnut Branches" and Paul Cezanne's "Boy in the Red Waistcoat."

A police handout shows the painting A police handout shows the painting 'Blossoming Chestnut Branches' by Dutch artist Vincent van Gogh (1853-1890). Paintings by Cezanne, Degas, van Gogh and Monet worth $164 million were stolen in broad daylight on Sunday from the private Buehrle Collection in Zurich, police said in a statement.

The FBI estimates the stolen art market at $6 billion annually, and Interpol has about 30,000 stolen works listed in its database. But while only a fraction of stolen art is ever found, such thefts are rare because of intense police investigations and the difficulty of selling the works.

"It's extremely hard, if not impossible, to sell these works," said Michaela Derra of Ketterer Kunst GmbH, a Munich, Germany-based purveyor of modern and contemporary art. "Maybe they think they can blackmail the insurance (companies) and get money for the paintings in return. But this is all speculation."

Police said the museum had not received any such demand.

Steve Thomas, head of art law at Irell & Manella LLP's Los Angeles office, said it was unlikely the robbery was commissioned by a private collector looking to stash art in a secret location.

He thought the motive most likely would be an insurance ransom, a reward or leverage for someone who could be facing prosecution for even bigger crimes.

"As values have skyrocketed, art has become more of a target, and we are seeing more and more major art thefts around the world," he said.

But funding for art museums, particularly in security, has not kept pace, Thomas said. "Even with the best of museums, with the best of security, with guards standing there, people still manage to get away with the art."

Buehrle, a German-born industrialist who provided arms to the Third Reich during World War II, amassed one of Europe's greatest private collections in the aftermath of the war.

At least 13 of the art works he owned at war's end were included on British specialist Douglas Cooper's "looted art list," which was used to recover pieces stolen from Jews by the Nazis.

A five-year, Swiss government study released in 2001 said Buehrle had acquired an unknown amount of "flight art" — works smuggled out of Axis-controlled areas by Jews and sold at rock-bottom prices to avoid confiscation by the Nazis.

"We couldn't examine the flight art acquisitions of Emil G. Buehrle systematically," the study into Switzerland's wartime cooperation with the Nazis said. But it added: "In general, there was more flight art available than looted art" and this was reflected in collections such as Buehrle's.

Daniel Heller, author of "Between Company, Politics and Survival: Emil G. Buehrle and the Machine Tool Factory Oerlikon, Buehrle & Co. 1924-1945," said Buehrle repurchased 77 paintings after the war from a Jewish dealer, after the Swiss high court ruled the works had been stolen.

The museum's catalog refers to those pieces as "acquired in 1951 from a private French collection," Heller said.

The current collection is housed in a villa adjoining Buehrle's former home where he stored art before his death in 1956.

"We are happy that no employees or visitors were hurt," museum director Lukas Gloor said at a news conference.

Gloor said the robbers stole four of the collection's most important paintings, but added that they appeared to have taken the first four they came to, leaving even more valuable paintings hanging nearby.

The museum also owns Auguste Renoir's "Little Irene" and Edgar Degas' "Little Dancer," but Gloor said the sheer weight of the paintings probably made it impossible for the robbers to take more.

Three other versions of the stolen Cezanne painting — perhaps the most famous of those seized — exist in the National Gallery in Washington, the Museum of Modern Art in New York and the Barnes Foundation in Philadelphia. Gloor estimated its value alone at $90 million.

The stolen van Gogh, he said, has special value because it was painted in the last six weeks of the artist's life.

Switzerland boasts a large number of outstanding art collections, some of which have been hit by thefts and robberies over the years.

Last week, Swiss police reported two Pablo Picasso paintings were stolen from an exhibition near Zurich. The two oil paintings — "Tete de cheval" ("Head of horse") and Verre et pichet ("Glass and pitcher") — had been on loan from the Sprengel Museum in Hannover, Germany.

Cortesi, the police spokesman, said police were pursuing the possibility the Picasso theft was connected with the Buehrle robbery.

In a robbery in the late 1980s, three armed men made off with 21 Renaissance paintings worth hundreds of millions of dollars from a Zurich art gallery. The case was made public in 1989 when FBI agents in New York arrested two Belgians and recovered stolen paintings.

In 1994, seven Picasso paintings worth an estimated $44 million were stolen from a Zurich gallery. They were recovered in 2000, and a Swiss man and two Italians were jailed for the theft. The stolen paintings included Picasso's "Seated Woman," and "Christ of Montmartre," which had been stolen from the gallery once before, in 1991.

Yahoo News