How do you persuade a child not to be afraid when he already has witnessed the most horrific terror imaginable--a massacre that killed his mother and two sisters and left his right arm shattered? It is hard, but Augustin Vazquez Ruiz tries.

Inside an examining room in this Langley Park health clinic, Vazquez leans over Geronimo, a tiny 4-year-old, and speaks to him slowly, lovingly, in the ancient Mayan language of their tribe, Tzotzil.

He strokes the boy's bullet-scarred chest and abdomen and holds his hands, one of which has only stumps for fingers. He explains that the doctor will listen to his heart and touch his body. Geronimo lies on the table, his almond-shaped dark brown eyes fixed on this man, his official guardian for now.

Vazquez turns to indicate the doctor may begin. "Esta tranquilo," he said to the Spanish-speaking nurse. "He is calm."

Geronimo Vasquez Ruiz, along with two other young Indian children who arrived in Washington last week for medical care, is the survivor of one of the darkest moments in Mexican history.

On Dec. 22, 1997, 350 Indian peasants were fasting and praying for peace in a chapel in Acteal, Chiapas, the southern Mexican state that is the seat of the Zapatista rebel army. In 1994, the Zapatistas--a group of mostly Indian peasants--had staged an armed uprising against Mexico's ruling party demanding better living conditions and more political rights.

Most of the peasants praying in Acteal were members of a pacifist Catholic lay organization that is sympathetic to the rebels but opposed to armed conflict. Their homes in nearby villages had been burned and ransacked by paramilitaries, and they were living in a temporary settlement.

That morning, they were attacked by a pro-government group armed with machetes and AK-47s.

After six hours of violence, 45 of the villagers--20 children, 18 women (five of them pregnant) and seven men--were dead. Twenty-six people, most of them young, lay wounded with permanently disabling injuries. Among them were Geronimo, Efrain Gomez Perez, now 4, and Zenaida Perez Luna, now 6.

"We came out to take care of the wounded," said Vincente Luna Ruiz, 28, who had found safety hiding in a ditch. He discovered his niece, Zenaida, with the back of her head blown off by a bullet, but alive. She lay next to her parents, a brother and two sisters. They were all dead.

Luna now cares for Zenaida in Acteal and accompanied her to Washington. He speaks in Spanish as he sits in the waiting room of a pediatric ophthalmologist's office near American University. "When the doctors first saw her, they said she would never see again or walk again," he said. "I cried very much because she had lost everything else."

Beside him, Zenaida tentatively touches a wooden toy on a low table. She has some sight remaining, but no one knows yet how much.

These rural children are thousands of miles from home, trying to cope, their guardians never letting them out of sight. The children have rejected fast-food burgers and long for their staples: beans and tortillas. They're fascinated by toy cars and planes, something they've never had. Zenaida is shy and quiet, held back by her poor sight. Geronimo is rambunctious. Efrain is temperamental, the aftereffect, his father believes, of the trauma of the massacre.

They and the adults taking care of them are staying at a former seminary near Catholic University, where the children can run until they get lost along the building's long corridors and in its big rooms. Yet they gaze longingly out the windows and delight if they see a squirrel.

"It's hard for the children. They want to be out in the country, like the birds," said Vazquez, who traveled with Geronimo to act as an interpreter. "To be in here for them is to be sequestered."

The children's trip to the United States and the bureaucratic obstacles they had to overcome to get passports--hurdles the Mexican government says were routine--generated front-page headlines in Chiapas and Mexico City. Ultimately, several members of Congress appealed to Mexican officials on the children's behalf.

"There is political significance to what we're doing because it's an opportunity to say a word about this problem," said the Rev. Pedro Arriaga, a Jesuit priest from Chenalho, Chiapas, who also is accompanying the children and their guardians. "The children opened the heart of everyone to the brutality of the massacre once again."

Who ordered the 1997 attack continues to be a matter of debate. Religious and human-rights groups and some independent analysts believe that the state government was complicit in the attack, and that the Mexican federal government should bear blame for not resolving the turmoil in Chiapas and ignoring numerous warnings that the conflict was about to explode.

After a year-long investigation, the Mexican government declared last December that the massacre grew out of longstanding conflicts between neighboring villages and that the presence of the Zapatista army contributed to the incident.

The government also concluded that some Chiapas police officers participated in the massacre and that other law enforcement authorities did not intervene quickly enough to quash the attack. Ultimately, 328 people were indicted in the Acteal massacre. So far, 57 have been tried and sentenced.

"It is a very complex situation," said Jose Antonio Zabalgoitia, minister for information and public affairs at the Mexican Embassy. But, he said, "trying to establish that someone would have ordered an atrocity for political reasons is a far-fetched contention."

The children were invited here by Sister Patricia Krommer, founder of the Humanitarian Law Project, and Kathryn Cameron Porter, president of the Human Rights Alliance. Krommer, who has worked on human rights for almost three decades, raised the money for the trip and persuaded doctors at Georgetown University and the Spanish Catholic Center Medical Clinic to donate their services. In April, she took members of five congressional staffs to Acteal, which has become a destination for numerous human-rights advocates since the massacre.

"I was really deeply affected by these people," Krommer said of the residents of Acteal, who live in makeshift wood and cardboard lean-tos and are supported by international humanitarian organizations. "They are exceedingly gentle and they are profoundly kind people."

By the end of last week, Michael D. Medlock, a pediatric neurosurgeon at Georgetown University Medical Center, had ordered a CAT scan for both Zenaida and Efrain, whose jaw was shattered by a bullet.

Medlock said he wants to determine how much brain damage Zenaida sustained and whether there are bullet or bone fragments that should be removed.

Efrain, whose jaw is wired together and who still has difficulty eating, was scheduled to see a cranial-facial surgeon and dentist. Geronimo eventually will need more skin grafting and tendon transfers to improve movement in his arm, and Medlock referred him to hand reconstruction and plastic surgeons.

The group members are here on a year-long visa, which allows time for medical treatment, although no specific decisions have been made yet.

At the end of a long day of doctors' visits, members of the group from Acteal don their native Indian dress and go to the National Shrine of the Immaculate Conception to pray in the chapel of the Virgin of Guadalupe, the patron saint of Mexico.

In the custom of the Tzotzil, in which the eldest male leads the prayer, Vazquez, 32, thanks God for their safe trip and asks the Virgin to help indigenous people find equality, justice and tranquillity. He prays for an end to massacres and wars everywhere and that the children will find help in Washington.

"No one of us wants to even lose a nail. We all want to be complete," he said later. "But the children are invalids. They were left incomplete."