A major collection of 56 Haitian paintings owned by a former aide to deposed president Jean-Claude Duvalier was discovered in a Northwest Washington warehouse yesterday by lawyers for the Republic of Haiti.

The paintings, including works by early Haitian masters Hector Hyppolite, Rigaud Benoit and Philome Obin, are owned by Claude Auguste Douyon, Duvalier's former private secretary, and were part of a traveling U.S. exhibit sponsored by the Smithsonian Institution in 1978 through 1982.

One of the collection's three works by Hyppolite, "Papa Zaca, Papa Augoun" -- probably the most valuable -- was missing from the warehouse, according to Walter Pozen, a partner in the law firm of Stroock & Stroock & Lavan, which is representing Haiti. The two Hyppolite paintings found are entitled "Le Baiser" and "La Famille."

"The mystery deepens . . . but we'll find the missing painting," Pozen said.

Attorneys for Haiti learned last month that a cache of Douyon's paintings has been stored for the past four years at the Security Storage Co. of Washington, 1701 Florida Ave. NW. Until the attorneys examined the paintings in storage yesterday, it was uncertain whether they were part of the prized Smithsonian-sponsored exhibit.

Thomas Vennum, an expert on Haitian art at the Smithsonian who accompanied the lawyers on their two-hour inspection, described the collection as "very representative" and "extraordinarily fine."

"Its real value is its broad representation of {most of} the earliest artists . . . the real top names that fetch the highest prices at auctions."

The collection was insured for nearly $250,000 when it toured the United States and Canada, according to Smithsonian officials, but the value has increased substantially since then, according to some experts.

Hyppolite's paintings generally sell for $15,000 to $30,000 apiece, according to Fritz Racine, a local collector, although a German collector paid $72,000 for one several years ago.

The works of other prominent Haitian artists generally sell for $15,000 to $20,000 apiece, experts say.

"The value of the collection is not to see it broken up but kept together, because it is so representative," Vennum said.

The Haitian government is attempting to recover $120 million allegedly stolen by Duvalier, his family and associates, including $1.3 million allegedly taken by Douyon.

The one-time private secretary used part of those funds to acquire the paintings before fleeing his country, according to lawyers for Haiti.

D.C. Superior Court Judge Emmet G. Sullivan signed a temporary restraining order Monday preventing Douyon or Marie Noel of Silver Spring, identified in court papers as Douyon's counsin, from removing the paintings from Security Storage.

A hearing on the case has been scheduled for Tuesday.

"It was a very exciting scene in the vault," Pozen said after yesterday's inspection.

"The pictures do have an intensity. There's all this voodoo and these historic scenes with very vivid colors."

The paintings represent the works of 34 of Haiti's best known artists, including many dating from the 1940s and 1950s.

The colorful, powerful works reflect a blend of the influence of African art and Haitian culture and nationalism.

Hyppolite, who died in 1948, was recognized as Haiti's foremost painter.

A one-time house painter and shoemaker, Hyppolite used chicken feathers and his fingers as well as brushes to produce his works. Experts say his familiarity with the Haitian supernatural world accounts for the spiritual quality that pervades each of his paintings.

Obin is recognized as the founder of the highly stylized northern school of painting, which depicts the physical isolation of his north coast home of Cap Haitien. Benoit, a taxi driver born in Port-au-Prince in the early 1900s, is best known for his imaginative and meticulous interior scenes. His work also reflects his devotion to the complexities of voodoo.

Other artists represented in the collection include Gerard Valcin, Andre Pierre, Volvick Almonor, Gesner Abelard, J.B. Bottex and Wilmino Domond.