Cold cases are notoriously hard for investigators to solve, and the killing at Arroyo Hondo Pueblo was no exception. Sometime in the A.D. 1350s, a respected Pueblo villager from the settlement, about 15 miles east of present-day Santa Fe, New Mexico, approached a four-year-old child. He lifted up a heavy grinding stone and then he sent it crashing down on the child’s head, shattering the skull and killing the child instantly. 

Someone, perhaps the same man, also knocked out five of the child’s teeth and clubbed him in the ribs on both sides of the torso, breaking them. Two other children, ages three and four, were killed the same way at the same time, according to evidence pieced together by archaeologist Ann Palkovich of George Mason University. All three children’s bodies were then tossed in the pueblo’s trash.

In today’s world, such a killing would be regarded as a heinous crime, and police and prosecutors would move heaven and earth to track down and convict the killer. Palkovich worked for years to solve this cold case. She conducted a detailed study of the children’s bones and artifacts from the site, and she drew from advances in forensic science and from ethnographic studies of more recent Pueblo people. That evidence pointed to a conclusion that’s shocking from a modern point of view, yet nonetheless true. “These kids were purposely killed to protect the village,” she says.

Archaeologists once hewed to the view that small-scale, tribal cultures lived a peaceful existence in an Eden-like world, says George Milner, an archaeologist at Pennsylvania State University. But in a widely noted 2011 book, The Better Angels of Our Nature, Steven Pinker, the prominent Harvard University psychologist, argued that people today are killing, raping, torturing, and battering each other far less than in the past. That’s largely because civilization maintains a rule of law that reins in dark forces like revenge, sadism, and tribalism that can drive people to violence, Pinker maintains. It’s a view in line with that of Thomas Hobbes, the 17th-century English philosopher, who argued that without modern civilization, life is “solitary, poor, nasty, brutish, and short.”

But over the past decade or two, archaeologists and anthropologists who study violence are uncovering a more complex—and more interesting—reality. “All of prehistory wasn’t peaceful or torn apart by war. It was, in fact, a bit of both,” Milner says.

That conclusion is based on the work of bioarchaeologists, who draw on archaeology, linguistics, biological anthropology, forensics, history, and cultural studies to examine violence past. As these researchers seek the roots of past battles, assaults, kidnappings, and killings, “we’ve gone from a descriptive science to a science that plugs into big fundamental questions about why humans do what they do,” says Debra Martin, a bioarchaeologist at the University of Nevada, Las Vegas and co-editor of the recently published book The Bioarchaeology of Violence.

In order to study ancient violence, researchers have to correctly identify it. That was the goal of Ventura Pérez, a bioarchaeologist at the University of Massachusetts-Amherst and another of the book’s co-editors, in a recent study on human bones found at Chaco Canyon, in northwest New Mexico. Other researchers had noted cut marks in human bones from Peñasco Blanco, a great house in Chaco. This led them to conclude that the Anasazi had killed and cannibalized humans. But Pérez knew that to people in some cultures the remains of family or high-ranking members of the community offer comfort or power to the living, so they let the bodies of these people partially decay, then cut them up.

To find out why Chaco’s residents were cutting up dead bodies, Pérez studied both human and deer bones obtained from Peñasco Blanco. When Pérez started, all he could say was that the bones, which were excavated in 1898 and are now stored at the American Museum of Natural History in New York, had been cut around the time their owners died. Pérez compared cut marks on human bones with those on the bones of deer the Anasazi consumed. 

Pérez made a plaster cast of each bone, used it at as a negative to make an epoxy cast replica, then took thin slices from the replica and looked at it under a microscope to observe the cut marks in detail. Compared with the cut marks on human bones, those on deer bones were “twice as deep and wide even though they were similar bones that were cut in similar joint areas,” Pérez says. That told him that rather than being cut up and eaten, the human bodies had been allowed to decay, then selected remains were processed by cutting off soft tissue. This finding revealed that a mortuary ritual—a ritual treatment of a dead human body, perhaps for religious purposes—had taken place rather than cannibalism.

The three children of Arroyo Hondo Pueblo (now a preserve of The Archaeological Conservancy) were killed for an entirely different reason, Palkovich has found. Her interest in their killings began as an undergraduate in the late 1970s, when she assisted during the original excavation of the site under the direction of Douglas Schwartz of the School of Advanced Research in Santa Fe, New Mexico. 

A later analysis of growth patterns in the children’s teeth revealed that when they died they were three, four, and four and a half, respectively. In addition, the children’s bodies “were dumped together and covered with dirt,” without the objects that connote a proper burial, Palkovich says. “That was the first clue that there was something unusual about these kids.” She created a chart listing which bones were present, and she analyzed them to determine how tall the children were and if there was evidence of disease. Then she noticed that all three children had cracks that radiated from the midline on top of the skull downward to its base.

In the late 1990s, Palkovich analyzed the bones one last time before their remains were reinterred under the guidance of Pueblo elders and in order to comply with the Native American Graves Protection and Repatriation Act. By then forensic scientists had learned that cracks in the base of a skull are the result of blunt-force trauma to the top of the head, and that this type of injury invariably kills the victim quickly. “So I can say with little doubt that someone hit those kids hard on top the head, that they had blunt-force trauma, and that they died as a result of those injuries,” Palkovich says. The original excavators also found a mano, a type of grinding stone, in a midden near the children’s bones. That may have been the murder weapon. 

“The question was, why were these kids beaten to death?” says Palkovich. To find out, she turned to ethnographic accounts of Pueblo Indians gathered between 1880 and 1940. Cultures have different ideas of what constitutes a full-fledged person, she says. In our society, we take for granted that a human being is a person who resides in his body from the day he’s born to the day he dies.

But in traditional Pueblo culture, personhood is conferred by a series of rituals, ethnographers had learned. “When you’re born, you’re a human being, but not yet a person because your spiritual existence is still in the underworld,” Palkovich says. A Pueblo child gained full-fledged personhood by undergoing a naming ceremony at four days of age, a water-giving ceremony at one year, a water-pouring ceremony between six and 10, and a finishing ceremony at 10.

The three children of Arroyo Hondo died at a time when drought and disease were killing both adults and children. According to ethnographic accounts, the Anasazi, who are generally thought to be the ancestors of the Pueblo Indians, blamed community-wide misfortune on witches—unwanted and dangerous spirits that possess human beings and bring trouble to the community. And the Anasazi viewed young children as innocents who were particularly vulnerable to possession by witches. So in times of misfortune, “they go looking for witches, and children are not exempt,” Palkovich says. 

Assuming the residents of Arroyo Hondo had beliefs similar to their ancestors, the evidence suggested a ritualized killing. The killer, Palkovich says, was someone with high standing in the community, like a judge or prosecutor in ours—“somebody who was sanctioned to face down a witch, which is a very serious matter.” The Anasazi faced down a witch by driving it from the human it had possessed, and the way to do that was by damaging his or her body beyond repair.

“People in the past faced a range of problems we face in society today, and wanted to act for the greater good of the community,” says Palkovich. “They were much like us. These decisions were probably not easy for them.” 

In the late 1200s, the Anasazi in the Mesa Verde region were facing desperation. Between 10,000 and 30,000 people had lived in the area for decades, but by 1280 they abandoned their homeland. Researchers learned, by analyzing the growth rings of trees that were extant then, that a severe drought had gripped the area from 1276 to 1299. They’d assumed that the drought had driven people from the region. 

Before the drought, the Anasazi grew corn, beans, and squash and raised turkeys for food. But by the late 1270s they were eating mostly wild plants and animals, including rabbits, coyotes, and bobcats, according to an ongoing study by Kristin Kuckelman, an archaeologist at Crow Canyon Archaeological Center near Cortez, Colorado. What’s more, the area’s pueblos had been built in easily defended spots, which suggested conflict. 

At the Castle Rock, Sand Canyon, and Goodman Point pueblos, Kuckelman and her colleagues found evidence of nonlethal fighting during the last years the pueblos were occupied, including bones with healed or infected fractures. She also found evidence of lethal trauma, including skulls with unhealed depression fractures. 

All told, Kuckelman and her colleagues found the remains of at least 35 people who died at Sand Canyon, 41 at Castle Rock, and 11 at Goodman Point. Many remains were in sprawled positions from being tossed through a roof hatchway or left on top of a roof. Because these were not respectful ways to treat the dead, it suggested that these deaths were the result of attacks from other villages or communities. What’s more, the archaeologists found skulls with cut marks above eye orbits or on the back of the head, which suggested scalping. 

Together, the evidence coalesced into a narrative: after decades of plenty that allowed the population to grow, severe drought had gripped this high mountainous area, destroying crops and turkey flocks, and forcing families to subsist on wild animals and plants. Villages competed for those wild plants and animals with other communities and probably raided each other’s storehouses. 

None of this explained the scalping. But ethnographic interviews of Pueblo people during historic times offered some clues. “At least two different ethnographers reported a belief among Pueblo Indians that scalps were powerful ways to bring rain,” Kuckelman says. “So if there’s drought, and a cultural belief that taking scalps could end drought and bring rain, then that’s a sanction for engaging in warfare.”

To understand the types of violence that cultures permit, it’s important not to impose preconceived notions, says Kathy Koziol, an adjunct professor of archaeology at the University of Arkansas. That’s what led earlier archaeologists astray when analyzing a group of 118 young women between 15 and 25 who had been killed and buried in four mass graves at Cahokia Mounds, a Mississippian site by St. Louis that was occupied between approximately A.D. 600 and 1400.

The Mississippian people buried their dead on top of existing graves, thereby creating mounds. Koziol focused on Mound 72, which contains “an interesting little mishmash of burials,” she says. When archaeologists Jerome Rose and Melvin Fowler first excavated Mound 72 in the early 1970s, their focus was understanding Cahokia’s socio-political structure, and one aspect of that was identifying the status of the individuals who were interred in the mound. 

Rose and Fowler discovered two individuals who were buried with a cape made of shell beads arranged in the shape of a falcon, which suggested they had high status and were probably chiefs or shamans. Nearby were four mass graves containing the women’s remains. Because they were killed together and buried, without any material goods, near the elite burials, the archaeologists had assumed they were lowly members of society who were sacrificed to the elite men. Case closed—or so they thought.

Koziol thought otherwise. “I found those interpretations very unsatisfying,” she says. To find out who these young women were, Koziol read all the published material on Mound 72, and then began examining Rose’s photos, data, and field notes from the original excavation. “I was excavating file cabinets,” she jokes. 

Rose and Fowler’s original interpretation of the Mound 72 burials applied an economic model based on the notion that the grave goods were a reflection of an individual’s status, and in doing so they glossed over the spatial and temporal distinctions in mound construction phases. Therefore important details, such as the determination that one of the four graves containing the women was in fact about 50 years younger than that of the elite men, was largely forgotten in future interpretations. “For 30 years people were married to this economic model,” Koziol says. “I was taking a whole new theoretical approach in interpreting those burials.”

Koziol noted the younger grave, and she also noted that the three other graves were buried in a section of the mound that, while unrelated to the area of the elite burial, was connected to a charnel house that could have held the remains of Cahokia’s elite. The charnel house was dismantled at the time of the women’s burials, which leads Koziol to conclude that the women were not sacrificed to the men, but were perhaps part of a charnel house closing ritual. 

The women in all four graves also had different dentition and diets from the other individuals buried in Mound 72, and their skulls and long bones showed little evidence of chronic infections, including nonvenereal syphilis, that was evident in the remains of Cahokians. That indicated they were from an outside group, and it’s likely they were captured because they were young and healthy. Since they all died and were buried together, they were almost surely killed, probably by strangulation or poisoning, which leave no marks on the skeleton, Koziol says. 

To find out why this happened, Koziol noted that the young women of Mound 72 were buried in neat, layered rows separated by woven mats. Another group of men and women who were later buried in the mound were killed violently by bludgeoning, and a third group of four men were killed and buried without their heads or hands. All these people were apparently assigned roles in the Cahokians’ central mythology of how the world came to be and people’s roles in it. “We don’t know all the details of that story,” Koziol says. “But we do know that the groups of people killed and buried here represent aspects of that story.” 

That story belongs to the captors, but the victims’ stories are equally important. “Sometimes when we just see people as victims, we tend to dehumanize them and not hear their stories,” Koziol says. Her research on the young women buried in Mound 72 was “a way of trying to humanize and personalize their stories.”

Gaining insights into the causes of violence matters today, according to Pérez. In addition to his work on ancient violence he’s studying the modern Mexican drug cartels’ practice of murdering people and leaving their mutilated bodies in public plazas or in front of police stations “to send a powerful message to rivals or police,” he says. The drug cartels consider this brutality to be an acceptable way to accomplish their goals. 

To understand violence, according to Pérez, is “to understand the transformative powers of its use in social relations and cultural practices.” And the study of ancient violence gives context to its modern counterpart. “By looking for the social, political, and environmental mechanisms that sanctioned violence in the archaeological record,” Pérez says, “we can better understand the variables that can produce violence today, and thus try to limit its use.”