MEXICO CITY -- For a dozen years, Nellie Campobello was a figure of mystery, a legendary writer and choreographer from Mexico's "Golden Age" who seemed only to speak to Claudio Fuentes Figueroa, a man once cleared on charges of kidnapping her.

Now, it appears Campobello has lain dead for a dozen years in a barely marked grave and officials are hunting for Fuentes, who has disappeared -- as has a treasure trove of Campobello's artworks."It is a gothic horror story . . . a tale of cynicism, arrogance and moral monstrosity. Fuentes pretended for so many years she was alive," said writer Carlos Monsivais, who signed a petition earlier this year asking authorities to look for Campobello.

Investigators said this week they have been unable to locate Fuentes recently. Mexico City Attorney General Samuel del Villar said he was seeking an arrest warrant for him.

During the past 12 years, Fuentes would regularly say he had recently talked with Campobello and that she was living a reclusive life in the rural central state of Hidalgo.

He even offered to lead investigators to her in August -- but halfway through the trip he reneged, saying he had changed his mind.

Authorities announced this week they had found her body -- in a rural graveyard in a tomb marked only with her initials. A death certificate filed in a nearby town indicated she died of heart failure at 86 on July 9, 1986. Fuentes signed the certificate as a witness.

But the mystery of the artworks, which Monsivais described as "national treasures," remains.

Campobello was a luminary in the Golden Age of modern Mexican culture in the 1920s to 1950s, contemporary and friend of the likes of Diego Rivera, Frieda Kahlo and Jose Clemente Orozco.

"She was a pioneer. She was the first to revive Mexico's folk dances and Indian dances," said author Elena Poniatowska. Campobello founded one of Mexico's famed Ballets Folklorico.

Orozco occasionally painted backdrops for her dances.

Campobello's two novels, "Cartucho" and "My Mother's Hands," received little recognition in her day but are now required reading at dozens of universities.

"Because she was a woman, and Mexico is a country of machismo, no one paid any attention to her" as a writer, Poniatowska said. In the last years of her life, few even saw her.

Monsivais described Campobello's last decade of life as similar to the Hollywood movie "Whatever Happened to Baby Jane," in which a character is watched over by her abusive sister.

Campobello lived in a run-down old mansion in Mexico City's downtown, watched over by Fuentes and his wife.

Fuentes had power of attorney and presented himself as her "compadre," a term meaning friend or godparent. It was unclear how the two first met.

Campobello had been reduced to a "terrified child" the last time Monsivais saw her in public, during an April 1985 hearing on criminal charges brought by a government arts council accusing Fuentes of having kidnapped her. A court dismissed the charges for lack of evidence.

In September 1997, Fuentes also filed a police report claiming that millions of dollars in artworks had been stolen. Those works presumably include a 1936 painting by Orozco commemorating the death of Spanish poet Federico Garcia Lorca.

"I don't think he (Fuentes) could have sold the Orozcos, perhaps works by Carlos Merida and Roberto Montenegro. But no one knows where they are," said Monsivais, who had seen the artworks and called them "of exceptional quality."