The mound of Dian Fossey's grave is rust-colored and freshly turned and it rises out of the tangled brush like a welt in an animal's hide. There is no marker, but the clearing, not far from the cabin where Fossey was found two days after Christmas, her skull split by blows of a panga knife, is studded with small wooden signs.

Red-lettered and rain-smeared, they are the headstones of the gorilla graveyard Fossey, 53, maintained during her 18-year reign as protectress and fierce patron saint of the rare and endangered mountain gorilla. The names are whimsical, affectionate and almost defiantly unscientific: "Uncle Bert" and "Digit," "Marchessa" and "Quince," "Frito," "Dude" and "Nunkie." Fourteen markers, fourteen gorillas, dead at poachers' hands or of natural causes, a macabre garden for the remote mountain research station Fossey founded in 1967.

The Karisoke Research Centre lies at 10,000 feet in the saddle between Mont Karisimbi (meaning snowcapped) and Mont Visoke, two of six volcanoes that form the Virunga range in Central Africa. Its mossy, rich rain forest is shared by Rwanda, Uganda and Zaire. It was to Rwanda's Parc des Volcans, only miles from where the borders join, that Dian Fossey arrived eager to begin her study of gorilla gorilla berengei, man's closest nonhuman relation.

Fossey never got around to installing a generator for electricity, but over the years there were improvements like glass windows and curtains, a latrine with a wooden seat, charcoal stoves and new cabins to accommodate the guests who came to study and learn.

Fossey had thrived, too. Six feet tall, shy and gawky but possessed of legendary physical courage, she became a member in good standing of the exclusive sorority of women primatologists.

Like Jane Goodall, the Englishwoman who had begun studying chimps a few years earlier in Tanzania, and the Canadian-born Birute Galdikas, who studied orangutans in Borneo, Fossey went to Africa with the blessing of anthropologist Louis Leakey and help from the National Geographic Society and other foundations.

National Geographic films and television specials, her articles and lectures in the United States and Britain and the 1983 publication of her book "Gorillas in the Mist" had made her name synonymous with the plight of the mountain gorilla well beyond conservationist circles. In June she had appeared on the Johnny Carson show for the first time. A Hollywood movie company was planning a film of her life, to star Sissy Spacek.

After the murder there were rumors, related with absolute conviction by Rwandans in the capital city of Kigali and in sleepy Ruhengeri, the provincial seat nearest her camp, about the circumstances of her death. Bizarre and untrue as most of the stories were, they were testament to the deep embarrassment felt by many at the death of the woman who many here credit with putting Rwanda on the map.

"It's a terrible blow for the Rwandans," said Rosamund Carr, a friend of Fossey and the widow of a British planter. "These are a very gentle and kind people, and they are grieving. I had a man come to my house after he heard about the murder on the radio. He said, 'Madame, is it true she has been killed?' I said yes, and tears began to roll down his face."

"She gave herself to our animals," said Aloys Mundere, a regional director of the official Rwandan weekly Imvaho. "Because of her, Rwanda and the park are known around the world."

There was one rumor that said the corpse had been found clutching a clump of blond hair, and hopeful speculation that the murderer had been a European. Still others believed that "l'assassin," as he was called in French-speaking Rwanda, had been a Twa poacher, a member of the forest-dwelling pygmoid tribe that makes up about 1 percent of Rwanda's population and the least-privileged rung of Rwandan society. Another rumor had it that the murderer was from Zaire.

Even if she hadn't been famous, the mere fact that Fossey was white would have been enough to make her murder newsworthy. In many parts of central and East Africa, whites lead charmed lives, deferred to and treated as honored guests. Rwanda, a former Belgian colony whose lush, mountainous terrain has given it the nickname Switzerland of Africa, has seen tribal warfare in past 25 years, but violence against whites is rare.

"Up to now, it was always thought that even poachers wouldn't kill a mzungu," said one American embassy employe in Kigali. Fossey was only the second white to be murdered in 30 years.

The murder also revived memories of the death of 69-year-old Austrian conservationist Joy Adamson in Kenya six years ago. Adamson, whose work with big cats was immortalized in the film "Born Free," was first reported to have been mauled by a leopard at her camp. It was later revealed that she had been stabbed to death by an itinerant camp employe.

From a distance, it is difficult to understand how anyone would want to harm the gawky woman from California, a self-described "hillbilly," so eager to take up her work that she'd had a preemptive appendectomy to persuade Louis Leakey that she was the woman for the job. "I had this great urge, this great need to go to Africa," she said years later. "I felt it from the day I was born. Africa represented freedom to me, adventure, total lack of restraint."

Her lack of scientific credentials were an asset. Leakey believed that a nonscientist might prove a more patient and less biased observer of animal behavior. For the first three years, longer than an academic might have been able to spend, Dian Fossey crawled through mud and rain, learning the gorilla vocal sounds and behavior, in order to be allowed to get close enough to begin her work.

At first the gorillas, the largest of whom stand six feet and weigh 400 pounds, would shriek their ear-shattering, knee-weakening screams and run (once or twice they charged; she sank to the ground and they lost interest). Gradually she won their trust.

"The gorillas have responded favorably, although admittedly these methods are not always dignified," she wrote in 1970. "One feels a fool thumping one's chest rhythmically, or sitting about pretending to munch on a stalk of wild celery as though it were the most delectable morsel in the world."

She struggled to overcome acrophobia on 45-degree slopes, wrestled with the local language (she never learned French or Kinyarwanda, the national languages, and used an imperfect Swahili). Most of all she fought the isolation, a syndrome she called the "astronaut blues," in which otherwise normal people disintegrate after a few weeks of loneliness on the mountain.

She survived, although later she would remember watching her guide disappear down the mountain on the first day at camp: "I had to hang on to my tent pole to keep from running after him."

Single-handedly she succeeded in discrediting the King Kong myth and revealed the mountain gorillas as shy and intelligent vegetarians who would choose flight over confrontation provided their young were not being threatened. Her labors provided a foundation for countless scientists who followed, and indirectly and unwillingly she laid the groundwork for the "gorilla tourism" that has become an increasingly important source of foreign exchange.

For better or for worse, Fossey made the gorillas her companions. Some, upon her death, would say this was her undoing, and that she loved animals more than people. Of course, it was more complicated than that.

"I have become well acquainted with many of the gorillas and they with me . . . and several groups now accept my presence almost as a member," she wrote in National Geographic in 1971. "I can approach to within a few feet of them, and some, especially the juveniles and young adults, have come even closer, picked up my camera strap and examined the buckle on my knapsack." In 1971, four years into her studies and about to leave Karisoke for a sojourn at Cambridge University, she made physical contact with a young gorilla named Peanuts who reached out and touched her hand during an observation session in the jungle late one afternoon. "I expressed my own happy excitement by crying. This was the most wonderful going away present I could have had."

Karisoke is an isolated place, even by African standards. To get there from the nearest town requires a two-hour ride north from Kigali to Ruhengeri, and then a bone-jolting hour's ride over lava rock "roads."

The last leg of the journey is a hike of two to three hours, up a narrow, at times almost vertical, mud track fringed with stinging nettle plants and hidden vines. Small game like the rodent-like hyrax and varieties of the African antelope called duiker fill the forest. But the park guards' rifles are meant for larger game, elephant and especially water buffalo, unpredictable creatures known to charge anyone who blunders too close.

The camp sits in a grove of large mossy Hagenia trees, beside a small stream. The cabins are made of corrugated metal painted green and lined with grass matting. Fossey's boasted a stone mantelpiece and a large photo gallery of gorilla faces. There is a red felt Santa Claus on her front door that reads "Howdy." The cabins are separated by distances of up to a hundred yards, and that distance is obscured by thickets of vegetation.

Darkness falls at 6:30. After that the paths to the cabins are illuminated only by flashlight or lantern.

Early on the morning of Dec. 27, Dian Fossey's longtime cook and houseman, a middle-aged Rwandan named Kanyaragana, walked the several dozen yards from the center of camp up the mud track to her cabin. Fossey had been suffering from insomnia for several years and frequently stayed up until 2 and 3 in the morning. As he approached the cabin in the early morning gloom he was surprised to find the front door wide open.

Inside, the living room was in disarray, the matting on floor awry, drawers opened. He looked into the bedroom and then ran down toward the cabin of a 34-year-old American scientist named Wayne McGuire.

McGuire was a graduate student from the University of Oklahoma and had only been at camp a few months. His Swahili was still rough, but that morning, still groggy, he thought he heard Kanyaragana shouting something about theft. "He was yelling 'Missing,' and 'Robbers!' " McGuire said.

There was ample reason to be apprehensive. Fossey herself was well aware of the dangers of living in such a remote spot. She had had a harrowing experience in her first six months in Africa, when her first camp in Zaire was attacked by Zairean soldiers who mistook her for a mercenary and imprisoned her for two weeks.

She often had warned camp researchers that if they ever heard shooting, day or night, they should drop what they were doing and flee, and she advised all camp residents to keep passport and rain gear in one spot "in case you have to run," one man remembers.

One researcher remembers being in Fossey's cabin several years ago when shouting broke out down in the center of camp. Later it was learned that a cabin had caught fire, but "Dian immediately assumed it was a kidnaping," said Kelly Stewart, a scientist and former researcher at Karisoke. "She locked me in the storeroom and loaded her gun."

McGuire pulled on his clothes and ran toward the cabin. "The living room was bad," he remembered later, "but the bedroom was a disaster."

Sheets, suitcases, clothes lay scattered across the floor, and there was a smashed lantern nearby. Fossey's body was lying face up on the floor alongside her large double bed. She was dressed in the long johns and sweaters she slept in; her slippers were still on her feet. Except for the pool of brown blood now soaking into the matting beneath her head, one might have thought she had simply fallen out of bed. A pistol and ammunition cartridge lay near her right hand, almost under the bed.

A doctor's examination hours later would show that Fossey had been hit six times with a panga knife, a long machete-like weapon with a two-foot blade common to Africa. Three of the blows were superficial; three were made with force, killing her almost instantly. "One of the blows had hit her right across the mouth," Wayne McGuire said. "The skull was split . . . she was cold as ice." Apart from a few bruises, there were no other wounds. The murder weapon, smeared with blood, was found under the bed.

McGuire got on the radio and called for help, but because of the distance and the holiday it would be hours before help would arrive.

In the weeks after her death there were scores of people in Ruhengari who claimed to have seen the body. Some claimed Fossey had been decapitated. Others talked of sexual and facial mutilation. No autopsy was performed because there were no coroners in Rwanda to do the job. Philippe Bertrand, a young French doctor from the hospital in Ruhengeri, was a friend of Fossey who had performed several autopsies on dead gorillas. He examined the body but declined to perform an autopsy because he said the cause of death was clear. He found the scene in the hours after the discovery of her body, when two dozen Rwandan armed police swarmed over the house, "disgusting."

A crawl space had been cut out of the wall opposite the foot of her bed with metal cutters, and the murderer also had hacked through the interior wall of grass matting. Other doors in the house had been unlocked.

Presents under the Christmas tree in the main room lay untouched; Fossey's gray parrots, Dot and Dash, were unharmed in their cage. Thirteen hundred dollars in U.S. currency was found in a desk drawer. Cameras, radio and bottles of liquor had not been touched, either, nor had her guns. Valuable camping equipment, as well as spears and other weapons confiscated from poachers, was undisturbed. The only thing missing was the passport.

McGuire said later that it appeared the house had been gone through as if someone were searching for something in a hurry.

According to eyewitnesses, the initial investigation was hampered by several factors. First and most important, say Europeans and Rwandans, Rwandan police are not accustomed to investigating this kind of murder. Fingerprinting and gathering of evidence is an unusual, rather than routine, practice. The investigation at Karisoke was rigorous but not particularly meticulous.

"Anyone who grew up on detective shows in the States would have been amazed at what was going on," says one person in camp at the time. The panga was gripped by several people during the course of the investigation. Objects were moved.

Although Fossey's gorilla trackers, the local men who follow the gorilla spoor to locate the study groups, are widely thought to be the best in the country, in the confusion and panic after the discovery of the body, no one thought to deploy them. There is no way to know whether the murderer or murderers fled down the volcano, or headed five miles due west, over Visoke's peak and into Zaire.

In the days after the murder, Fossey's friends and acquaintances turned over the details and struggled with the inconsistencies. How did anyone hack through a metal wall without giving Fossey enough time to defend herself? And even if Fossey, who was known to drink heavily, didn't hear the entry, and even if her cabin was set apart, how could the noise have failed to wake anyone else? Did she scream?

And why was the house ransacked but only the passport removed? Everyone in camp, and most poachers, knew that Fossey kept and used guns. Who would have been bold enough to invade her room? It was even more curious that her attackers had managed to find, by accident or design, the one place in the bedroom wall that was not blocked by heavy furniture on the inside.

Some speculated that Fossey had failed to waken because poison had been placed in her food. In Rwanda, particularly in remote areas near the Zaire border, traditional practices and beliefs flourish and death by poisoning is not uncommon. Poisoning suggests, however, that whoever murdered Dian Fossey knew her well enough to get close to her food. Fossey's associates say they doubt that anyone in camp had motive for murder, but Rwandan authorities have arrested most of the camp workers.

Philippe Bertrand, the doctor, believes it was Fossey herself who ransacked her room in the dark, scrambling to find her gun. Others say this is unlikely because she always kept her weapons readily accessible.

Dian Fossey always said she wanted to be cremated and her ashes scattered over the volcanoes, but in heavily Roman Catholic Rwanda cremation was not to be. The marker for her own grave, when it arrives from the United States, will read, as she had asked, one word: "Nyramachabelli," her nickname in Kinyarwanda.

In Rwanda, as in other African countries, children are given nicknames by their adult relatives, names that describe a particular physical or personality trait. Whites, too, are given nicknames, often ironic, sometimes unflattering. A white will usually be given a more flattering version of the nickname if he or she insists on knowing it.

Fossey repeated with pride to friends and journalists that Nyramachabelli meant "the old woman who lives alone in the forest." Others have said it means "the old woman who lives in the forest without a man." The director of the government newspaper in Ruhengeri insists the name can mean either a small girl, or "a small, energetic woman who works with the strength of a man."

A Rwandan economist says that Nyramachabelli is Kinyarwandan for a woman who dresses badly. Friends say this last has the ring of truth, for in northern Rwanda in 1967 a towering white woman wearing men's bush jackets and worn jeans was a sight worthy of comment.

It is said that the porters Fossey employed to lug supplies up and down the slopes were astounded at her ability to make the long climb without tiring.

They and many others were soon to be even more amazed at the ferocious and personal battle she would wage against the poachers, the range cattle and the human population that was pushing the mountain gorilla to extinction.

That battle only intensified as the years went on, along with her eccentricities, her loneliness and isolation, her often stormy relations with former researchers and her cool disdain for some Rwandan government officials.

She relished and encouraged her reputation as a white witch, learning to twist bits of grass and cloth in shapes that could make a poacher shake and weep. Over the years dozens if not hundreds of poachers had been hauled into her camp for interrogation and punishment. There were tales of torture. She destroyed thousands of duiker snares, confiscated spears and pangas, set fire to a poacher's hut and was charged once with kidnaping a poacher's child.

She was a creature of enormous contrasts, craving human company but often lacking the self-confidence to accept it; a woman with several close Rwandan friends who until a few years ago routinely referred to Africans as wogs. She disdained creature comforts, but had a weakness for fine clothing and shopped at Saks and I. Magnin when she could. She retained a wry sense of humor and was capable of joking, as she did recently upon receiving a new friend at camp, "I'm not an old bitch, I'm a young bitch."

Like the gorillas she fought for, she was given to vociferous displays of temper and aggression, but usually they were just performances, friends insisted.

Not everyone could tell the difference or cared to. "I worried about Dian for 18 years," said Rosamund Carr. "From the very beginning she was a girl who was completely uncompromising in her aims."

Tomorrow: Dian Fossey's private war.