The sleuth's name is Ruth Bowman. Her first clue was a photograph; her second was a thread.

Though the objects of her search had been cunningly concealed (and though much crucial evidence had been wantonly destroyed), Bowman persevered until the Gorky case was solved.

It was her detective work that led to the rediscovery of the Arshile Gorky murals, painted on canvas, which go on view today at the Hirshhorn Museum and Sculpture Garden.

His real name was Wosdanig Adoian -- "Arshile Gorky" was an alias. Although he was Armenian, he said that he was Russian, had been trained in Paris and was Maxim Gorky's cousin.

Such claims were lies, perhaps. But "dreams," said Arshile Gorky, "form the bristles of the artist's brush." All his life he dreamed -- of apricots, enigmas, airplanes, onions, feather -- and his dreaming, in the 1940s led the painters of New York towards a wholly abstract art.

When, in 1936, he began to paint the Newark Airport murals that are the subject of this show, he was not yet a master. Gorky, in the '30s, was still working in the styles of Miro, Leger, Picasso -- painters better than himself.

The most impressive fact about the murals at the Hirshhorn is that they're there at all.

Gorky painted 10 of them. Eight, it is presumed, have long since been destroyed. The other two were found, thanks to Bowman's sleuthing, beneath 14 layers of cream, beige and green paint.

Bowman is an art historian in charge of the collection at New York University. Among the paintings there is an untitled Gorky from 1935. Bowman knew it well. One evening in 1972, while leafing through a textbook, Bowman came across a photograph of one of Gorky's oil-on-canvas Newark murals. Suddenly, she realized that the painting at her gallery was related to Gorky's long-lost work.

"I was lying on the bed in Essex, Conn., when I saw the link. The connection popped out at me. I became a Gorky fanatic there and then."

The next morning she discovered that the smaller picture had not been, as she'd suspected, a detail cut from the Newark mural. Could it be, she wondered, that the murals were still there?

An inspection of the airport building soon produced the answer when a single thread of canvas was discovered sticking out of the much-painted wall.

Gorky worked for the WPA when the murals were commissioned, along with some 4,000 other murals sponsored by the government during the Depression. Gorky was paid about $25 a week. The 10 large works he painted cost the Newark Airport an additional $900 -- or 60 cents a square foot.

By the standards of the '30s, Gorky's Newark Murals, with their panels of flat color, their blobs and lines and dots, seemed suspiciously abstract. When Fiorello La Guardia, the mayor of New York, saw the painter's plan he said, "If that's art, I'm Tammany Hall."

But Gorky's scheme does not seem mysterious today. The shapes of airplane parts and maps, of theremometeers and wind socks -- considerably simplified, but nonetheless recognizable -- will easily be found by anyone who studies Gorky's Newark art.

Gorky's forms, like planes themselves, seem ponderous yet airborne. When it opened in the '30s, the new facility in Newark was among the most important airports in America. The 10 large pictures Gorky made might have been preserved, had not the U.S. Army Air Force taken over the building during World War II.

In the spring of 1940, the murals were photographed in place, still in fine condition. When the war was over, they were nowhere to be seen.

Bowman suspects that some of them, already painted over, were stripped away when radiators were installed in the early '40s. The rest were probably removed in the 1960s when new offices were built. It is something of a miracle that two managed to survive.

They were not Gorky's last murals. In 1938 he began to paint another work -- on the same theme -- for the Aviation Building designed by William Lescaze and J. Gordon Carr for the 1939 New Yok World's Fair. He also painted murals for Ben Marden's "Riviera," a Fort Lee, N.J., nightclub with a sliding roof, which opened the same year. Both the Aviation Building and the Riviera, and the murals in them, have long since been destroyed.

"Who cares?" asked one World's Fair official at the time. "Why do murals have to be permanent? Paint 'em out when you don't like 'em anymore."

"Murals Without Walls: Arshile Gorky's Aviation Murals Rediscovered" was organized by the Newark Museum. The show also includes models, photographs, documents, drawings and oil paintings that place the murals in the context of Gorky's '30s work.

Another Gorky exhibition, of 21 paintings and eight drawings, all from the Hirshhorn's collection, is also on display. (Joseph H. Hirshhorn, the museum's founder, visited the artist -- and bought 17 small Gorkys -- in March 1943.)

Though only Gorky's last great works are sure to be remembered, the seeds of his accomplishment are apparent in his murals. When he made them, he was still in thrall to his teachers, but in painting at large scale, and in distilling and abstracting forms that all could read, Gorky was proceeding to his later, greater art. Without the mural project of the WPA, the wall-sized works of Pollock, of Clyfford Still and Rothko, might never have been painted. Making murals was for Gorky a sort of liberation. The two Hirshhorn exhibitions remain on view through Nov. 25.