CHONTALA, GUATEMALA -- The mist-shrouded highlands here are Guatemala's killing fields, where tens of thousands of Mayan Indians were wiped out in the early 1980s in a counterinsurgency program that was probably Latin America's most sustained and efficient massacre in recent history.

Public airing of what happened has been taboo in Guatemala, largely because the terror wrought by the army and its surrogates, called civil patrols, has slowed but never really stopped. Like the uncounted victims decomposing in the acidic, volcanic soil, the truth here is underground.

Which is exactly where Clyde Snow, a craggy Oklahoman with a slow drawl and a quick wit, intends to find it. "The ground is like a beautiful woman," Snow said with a twinkle, gnawing on a Hoyo de Monterey cigar. "If you treat her gently, she'll tell you all her secrets."

Snow is probably the United States' most renowned grave-digging detective, the grand old man of an elite academic specialty known as forensic anthropology. From painstaking examinations of skeletal remains, some of them decades old, he reconstructs causes of death and, in the case of Guatemala, often grisly bits of history that officials have decreed dead and buried.

His work, under the sponsorship of the human rights groups Americas Watch and Physicians for Human Rights, is testing the stated commitment of Guatemalan President Jorge Serrano's civilian government to justice and human rights. And it is challenging the army and its civil patrols to face up to their role in the murderous counterinsurgency campaign of the 1980s.

"People will never respect the law until there's justice, and a good place to start is with murder" cases, Snow said. "If you can make people feel they're not going to get away with it... . That's all we're asking -- that you go to court and stand up to be judged."

But in Guatemala, that is quite a bit. The justice system here has never really called military men to account for the killings that are part of everyday life. Serrano came into office this year pledging to change the system, and there have been prosecutions in several high-visibility human rights cases. So far he's been supportive of Snow's work, even providing police protection for Snow's exhumations.

But here in the highlands, about 80 miles northwest of the capital, the reformist impulse is a distant echo. When Snow began his exhumations this summer, the local civil patrollers, who are suspected in many of the killings, spread the story that Snow meant to make a broth of the old bones he unearthed, spiced with onions and tomatoes.

Some villagers who have helped him to locate unmarked graves or identify old bodies have been threatened. Briefly in August, the president of the supreme court ordered a halt to the excavations. He said the civil patrols were intimidating villagers who were helping Snow and his team of young Guatemalan doctors, archaeologists and anthropologists.

Snow, of Norman, Okla., has dug up evidence of Custer's Last Stand at Little Bighorn, the victims of American mass murderers Ted Bundy and John Wayne Gacy, and victims of Argentine military repression in the 1970s. In Brazil, he identified the remains of the infamous Nazi death camp doctor Josef Mengele. And as a consultant for NASA in the 1960s, he tracked down survivors of suicide jumps from San Francisco's Golden Gate Bridge to assess the impact of free falls on bone structures. (He said most of the survivors mentioned a change of mind on the way down.)

This career has made him a highly paid consultant, the subject of a laudatory book and something of an American folk hero. His extensive work in Latin America, especially Argentina, has left him with a selective Spanish vocabulary, specializing in the lexicon of restaurants, bars and morgues.

But despite his breadth of experience, Snow said he has never worked anyplace quite like Guatemala, where, as he put it, "people get killed as if they were some sort of particularly noxious agricultural pest."

Human rights groups have blamed most of the killing on the Guatemalan army, which ruled almost continuously until 1986. By most accounts, the army's strategy was to defeat the guerrillas by forcing civilians to take sides: Those who backed the rebels, or perhaps only tolerated them, often were eliminated. Those who fought them, such as the civil patrols, were rewarded.

"The army said we had to take action against the guerrillas, or else it would be us who were responsible," said Tomas Tol Cagua, a former civil patrol member near the village of Chontala. "We were humiliated and scared, but the army would kill us if we didn't obey."

The result was a strategy of such brutality that "the Guatemalan Solution" has become shorthand in Latin America for wholesale, indiscriminate killing. While it did not erase the insurgency completely, it left the rebels unable to mount a serious military threat. But at the same time, the army's strategy caused untold numbers of civilian casualties, with entire villages razed in a scorched-earth campaign.

"It's too bad {Milwaukee mass murder suspect} Jeffrey Dahmer didn't come to Guatemala 'cause he'd be a general by now," Snow said with disgust. "In my line of work, you hear a lot about Guatemala. It's like the Old West, like the frontier, like 'Shane.' It's like every cliche you can think of: white hats, good guys, bad guys, vigilantes, the marshal coming to town. ... It's almost like the movies being replayed."

If there's a marshal in this script, it's the Texas-born Snow. At 63, his face has turned jowly and his eyes are hooded. But his savvy and his knapsack of tools and his battered green canvas hat still give him the air of Indiana Jones -- with a few years' extra mileage.

In his wallet he carries a heavy gold badge, which turns out on close inspection to be from the Illinois Coroners' Association, for which he has worked. "I'm not going to back off from the civil patrols," he said. "They have these little tin badges, and you know, when you get in a problem with local law enforcement, whoever has the biggest badge wins."

To Indian peasants who have watched Snow work, he is something of a magician. It is unheard of here to defy the civil patrols, let alone unearth evidence of executions. To the civil patrols, Snow is a threat, and they have told villagers that he is really a guerrilla masquerading as a gringo man of science.

On a gray afternoon, as the clouds swept in over the volcanoes on the horizon, Snow led a few journalists through lush cornfields atop a wind-swept ridge. When he arrived at the dig, his team was already scraping away the rich soil with trowels and soft brushes. A skeleton, still fully clothed and wearing rubber boots, was beginning to emerge from a three-foot-deep pit.

A few policemen hung around the fringes, along with a local judge and perhaps a dozen Indians -- laconic men in plain Western dress and stout women in the brilliantly colored heavy blouses that are characteristic of the area. A radio blared pop music.

This was the 27th skeleton Snow has unearthed since he began working in Guatemala this year. Before the bones were swept free of dirt, Snow was already noting its distinctive appearance -- part of a pattern repeated in each excavation he has made in Guatemala.

"We're beginning to see characteristics that are typically Mongoloid," he said. The skeletons are short, with prominent brows, heavy cheekbones, shovel-shaped incisors and a low nasal bridge that creates a broader nose.

Snow said the basic structure of all the skulls he has seen is the same: Indian, usually male, in the teens and twenties. Almost no mestizos -- people of mixed Indian and European blood.

In Guatemala, the killings in the countryside targeted poor Indians almost exclusively. The effect was to reinforce an already intense division -- mestizos vs. Indians, which often means haves vs. have-nots. That has been a lesson for Snow, and a sharp contrast with other countries where he has found evidence of mass murders, such as Argentina.

"In Argentina, the repression was directed at a very different social class, upper-middle-class people and intellectuals, the middle class. About a third of the victims were females," said Snow. "Here that's not the case. We're digging up Indian males."

The skeleton emerged from its grave and the bones were placed one by one on a sheet of cardboard nearby. Dirt around the body was collected and sifted for clues: a bullet fragment or casing might be found. Examining the bones one by one, Snow noticed some fragmentation behind the ear and first vertebra, and guessed that the man may have been shot with a small-caliber bullet in the base of the neck. His preliminary conclusion was later borne out on closer inspection in the morgue.

"Every bone has got its own little story to tell, like a finger bone with a fracture might identify someone through a medical history," Snow said.

Before this site, Snow or teams he trained exhumed at least four others in Guatemala. In the first, he said, were the remains of a man who evidently had been tied to a tree and killed by repeated blows from a machete to his back. Interviews with people in the area indicated the army had made villagers take turns hacking as a way to spread blame for the execution. Even the man's relatives were forced to take part, Snow said.

The next three digs unearthed multiple victims. In one, Snow said, there were six cadavers, apparently mowed down, then burned. Heavy-caliber, copper-jacketed bullets were found at the site.

In another grave were another seven skeletons, each shot in a similar manner. And in another, Snow said, he found 13 bodies, all with hands tied behind them and with close-range .22-caliber gunshot wounds in the skulls.

While the work has proceeded apace, there have been frustrations, Snow said. One has been putting together a team with the commitment, expertise and patience to maintain the work in his absence.

Another challenge is finding the graves in the first place. Most are unmarked, and Snow and his team have no funds for ground-penetrating radar, a $20,000 device that can detect subsurface irregularities. Rather, they must rely on the help and memories of villagers, many of whom have been intimidated by the civil patrols.

Perhaps the most formidable obstacle has been communicating with reticent Indians, many of whom speak little or no Spanish. Snow said he relies on a young Guatemalan anthropology student to draw the villagers out, but the job is difficult and at times tedious.

"Here we have cultural problems, linguistic problems, you name it," he said. "But there are good reasons to do it. One is humanitarian: It's very cruel not to know what happened to your loved ones -- just like with the families of MIAs. The whole process of grieving is suspended, it goes on for many years and passes from one generation to another. Very often, once the families have the bones, it helps them get over the process of grieving and get on with their lives.

"There's a chance for justice. If there's the ability and will to prosecute, the scientific evidence we gather can be used in trials.

"There's the historic record, so revisionists can't come along and say, 'No, this didn't happen.' It's very difficult to argue with a skull with a bullet in its head."