LONDON — A naked goddess, an intrepid war correspondent, Adolf Hitler's inner sanctum and the secret wartime journey of a 500-year-old painting worth millions of dollars.

Art stories don't come much more Indiana Jones than this.

Britain's National Gallery announced yesterday that new research has disclosed that a painting in its collection, "Cupid Complaining to Venus," by the German Renaissance artist Lucas Cranach the Elder, was once part of Hitler's private collection.

"We've never had anything like this before," said museum spokesman Thomas Almeroth-Williams. "It's incredibly rare."

The museum is investigating to determine the exact provenance of the painting, which was painted in about 1525, with particular emphasis on whether it might have been looted from Jewish owners by the Nazis.

So far, Almeroth-Williams said, the museum's experts have been unable to account for the painting's ownership or whereabouts from 1909, when it was sold at auction in Berlin, to 1945, when U.S. soldiers allowed a U.S. war correspondent — Patricia Hartwell, who lived in Hawai'i from 1971 until her death in 1998 — to remove it from a warehouse of art they were guarding in southern Germany.

CREDIT RESEARCHER

A researcher, Birgit Schwartz, who has been studying Hitler's art collecting, spotted the painting in a photograph of Hitler's private gallery contained in an album at the Library of Congress in Washington.

She recently brought it to the attention of the National Gallery, whose experts have concluded that the painting in the photograph is the same one now in the gallery's possession, Almeroth-Williams said.

While such a discovery is startling, art dealers said it is typical of how paintings and other works of art often become as famous for their journeys over centuries as for their brush strokes.

"Whenever I sell a painting, I always tell people, 'It's not just a painting, it's a little piece of history,' " said Peter Nahum, a London art dealer. "It takes you to another world — and this one has already taken you into Hitler's private collection."

The painting, an oil-on-wood work measuring 33.2 by 22 inches, shows Cupid complaining to a naked Venus that he has been stung by bees after stealing honey from their hive. According to the gallery, the painting's message is that "life's brief pleasure is mixed with pain."

The National Gallery bought the painting in 1963 from New York art dealers E & A Silbermann, who told the gallery that they had purchased it from "family descendants" of the buyer at the 1909 Berlin auction.

Almeroth-Williams said that now seems to be incorrect. What is known, he said, is that the painting was part of a collection belonging to someone named Emil Goldschmidt, of Frankfurt, auctioned in 1909. The identity of the buyer is still not known, he said.

NAZI LOOTING CONCERNS

In 1999, given growing concerns about Nazi looting of art, the gallery posted the painting on its Web site with 120 others whose ownership and location were unclear during the Nazi era, 1933 to 1945.

In December 2004, Almeroth-Williams said, the gallery received an e-mail from Jay Hartwell, a faculty adviser to the student newspaper Kaleo at the University of Hawai'i, who said his mother, Patricia Lochridge Hartwell, of Kane'ohe, had owned the painting from 1945 until she sold it to the Silbermanns in 1963. Hartwell said yesterday he wanted to help the gallery "perhaps find the painting's rightful owner."

Patricia Hartwell, who died at age 82, was a 1938 graduate of Columbia Journalism School who spent decades as a radio and print reporter, her son said in a telephone interview.

She first joined CBS Radio, then wrote about the war in the Pacific and in Europe for Collier's and Woman's Home Companion magazines. She was present at the iconic raising of the U.S. flag over Iwo Jima in February 1945 and the liberation of the Dachau concentration camp in Germany two months later, her son said.

According to the National Gallery, in 1945 she was allowed to take a painting from a warehouse full of art that was then controlled by U.S. forces. Jay Hartwell, a former Honolulu Advertiser reporter, said that is how he and his family understand the story, but he said, "I am unable to verify exactly what happened. We just don't know."

She then took the painting with her back to the United States, and her son said he recalled it hanging in their New York home.

LONGTIME ARTS CAREER

Patricia Hartwell had a clear interest in art. After the war, she joined UNICEF in New York as director of information, which required her to travel the world buying paintings to use for UNICEF Christmas cards, said her son.

She moved to Arizona and became director of the Scottsdale Fine Arts Commission, overseeing construction of the city's Center for the Arts. After moving to Hawai'i in 1971, she was involved with the Arts Council of Hawaii.

Patricia Hartwell and her husband approached the Metropolitan Museum of Art in New York in 1961, seeking to sell the painting, said Jay Hartwell. She sold it two years later to the Silbermanns.

The Art Newspaper, the bible of the art world, first reported Patricia Hartwell's connection to the Cupid painting in November 2006. The painting's connection to Hitler emerged only when researcher Schwartz approached the gallery recently. According to Almeroth-Williams, Schwartz spotted the painting in a photograph from a catalogue Hitler kept of his collection. The catalogue is now housed at the Library of Congress.

Gallery officials would not estimate the value of the Cranach painting, and neither would a spokesman for Christie's, the auction house. But Christie's said the record price for a Cranach painting at auction was $8.6 million in 1990, in London.

Cranach, suddenly, is something of a celebrity in London. Coincidentally, the Royal Academy of Arts has just opened a major exhibition of his work. Huge posters for the exhibition featuring a nude in the style of his Venus are displayed in London subway stations.