Farmer flashed a smile. "You’ll spend less time in Purgatory." Then he asked, "Who cut off the head of the assistant mayor?"

"I don’t know for sure," said the captain.

"It’s very hard to live in Haiti and not know who cut off someone’s head," said Farmer.

A circuitous argument followed. Farmer made it plain he didn’t like the American government’s plan for fixing Haiti’s economy, a plan that would aid business interests but do nothing, in his view, to relieve the suffering of the average Haitian. He clearly believed that the United States had helped to foster the coup–for one thing, by having trained a high official of the junta at the U.S. Army’s School of the Americas. Two clear sides existed in Haiti, Farmer said–the forces of repression and the Haitian poor, the vast majority. Farmer was on the side of the poor. But, he told the captain, "it still seems fuzzy which side the American soldiers are on." Locally, part of the fuzziness came from the fact that the captain had released the hated Nerva Juste.

I sensed that Farmer knew Haiti far better than the captain, and that he was trying to impart some important information. The people in this region were losing confidence in the captain, Farmer seemed to be saying, and this was a serious matter, obviously, for a team of nine soldiers trying to govern 150,000 people.

But the warning wasn’t entirely plain, and the captain got a little riled up at Farmer’s denunciation of the School of the Americas. As for Nerva Juste, he said, "Look, that guy is a bad guy. When I do have him and the evidence, I’ll slam him." He slapped a fist into his hand. "But I’m not gonna stoop to the level of these guys and make summary arrests."

Farmer replied, in effect, that it made no sense for the captain to apply principles of constitutional law in a country that at the moment had no functioning legal system. Juste was a menace and should be locked up.

So they reached a strange impasse. The captain, who described himself as "a redneck," arguing for due process, and Farmer, who clearly considered himself a champion of human rights, arguing for preventive detention. Eventually, the captain said, "You’d be surprised how many decisions about what I can do here get made in Washington."

And Farmer said, "I understand you’re constrained. Sorry if I’ve been haranguing."

It had grown dark. The two men stood in a square of light from the open barracks door. They shook hands. As the young doctor disappeared into the shadows, I heard him speaking Creole to his Haitian friends.

I stayed with the soldiers for several weeks. I didn’t think much about Farmer. In spite of his closing words, I didn’t think he understood or cared to sympathize with the captain’s problems.

Then by chance I ran into him again, on my way home, on the plane to Miami. He was sitting in first-class. He explained that the flight attendants put him there because he often flew this route and on occasion dealt with medical emergencies on board. The attendants let me sit with him for a while. I had dozens of questions about Haiti, including one about the assistant mayor’s murder. The soldiers thought that Voodoo beliefs conferred a special, weird terror on decapitation. "Does cutting off the victim’s head have some basis in the history of Voodoo?" I asked.

"It has some basis in the history of brutality," Farmer answered. He frowned, and then he touched my arm, as if to say that we all ask stupid questions sometimes.

I found out more about him. For one thing, he didn’t dislike soldiers. "I grew up in a trailer park, and I know which economic class joins the American military." He told me, speaking of Captain Carroll, "You meet these twenty-nine-year-old soldiers, and you realize, Come on, they’re not the ones making the bad policies." He confirmed my impression, that he’d visited the captain to warn him. Many of Farmer’s patients and Haitian friends had complained about the release of Nerva Juste, saying it proved the Americans hadn’t really come to help them. Farmer told me he was driving through Mirebalais and his Haitian friends were teasing him, saying he didn’t dare stop and talk to the American soldiers about the murder case, and then the truck got a flat tire right outside the army compound, and he said to his friends, "Aha, you have to listen to messages from angels."

Excerpted from Mountains Beyond Mountains by Tracy Kidder Copyright© 2003 by Tracy Kidder. Excerpted by permission of Random House, a division of Random House, Inc. All rights reserved. No part of this excerpt may be reproduced or reprinted without permission in writing from the publisher.