They brought out the victims using a helicopter with a cargo net dangling beneath. Soldiers wearing rubber gloves and masks unloaded body bags and laid them in the broad shade of an acacia tree. Forensic investigators began to work.

By the end of Thursday, the bodies of 12 farmers had been pulled from a war zone near the village of Naya, a daylong walk to the west of Timba in this embattled region 220 miles southwest of Bogota. Ten had been killed by machete; two had been shot. At least one was decapitated, the head still missing.

The grim business of preparing the bodies for burial, watched from across a soccer field by the mostly black residents of Timba and clusters of refugees from Naya, followed one of Colombia's largest civilian massacres in years. Beginning the Wednesday before Easter, a squad from Colombia's right-wing paramilitary force entered Naya and its surrounding hamlets. For three days, as the government army tried to reach the jungle town amid fierce fighting, Colombian officials say, paramilitary troops used machetes, guns and chain saws to kill at least 40 civilians.

In interviews with some of the 160 Naya families sheltered in the town school, survivors said the number of dead might be twice that amount. Colombian officials, who are continuing recovery efforts, agreed. The only recent killing of comparable size came four months ago in the village of Chengue, where paramilitary fighters killed 26 farmers with stones and a sledgehammer.

Apart from its size, the Naya massacre has frightened survivors and top Colombian officials for the way in which the paramilitary group, the United Self-Defense Forces of Colombia (AUC), carried out the killings. The use of chain saws and machetes in Naya, as well as rocks and hammers in other places, suggests a gruesome turn in Colombia's long-running war: As rightist paramilitary forces and the leftist guerrillas whom they battle gain strength, the method of killing has become its own message.

"Maybe they don't want to waste a single bullet on us," said Rafael Caso, whose 25-year-old son, Wilson, was identified in the open-air morgue, which filled the town with the smell of decomposed bodies. "No one knows why they are killing us this way. To clean everyone out is their idea. But why us?"

In a strategic sense, the savagery advances the AUC's goal of emptying out civilian populations used by guerrilla armies for supplies and support. Paramilitary forces, whom the government blames for the majority of civilian massacres, now have a stranglehold on many areas where they have carried out brutal killings, which they refer to as "cleaning."

One result is an internally displaced population of more than 2 million people, concentrated mostly in urban centers where the AUC already enjoys a large measure of control.

Explaining the rationale behind the AUC massacres, Luz Eugenia Vasquez of the Interior Ministry's human rights office said, " 'All men are equal, but communists are not men and so not equal to me.' This attitude negates the theory of human rights that most of the rest of the world subscribes to."

Vasquez, who spent Thursday helping identify the first wave of bodies brought here, said the recent savagery echoes a period five decades ago known as "The Violence" when partisan politics turned into open war. Pregnant women were killed, their breasts cut off, to drive people out of certain regions. Now the rising paramilitary movement has resurrected those tactics.

After visiting Naya soon after the killings, Colombia's ombudsman, Eduardo Cifuentes, warned that "we have returned to the most barbaric era," and reminded the country that the carnage is not "from a movie" but is a fact of modern life for peasants. A 17-year-old girl had her limbs cut off with a chain saw taken from a Naya farmer. Another was eviscerated. The bodies were left for a week in a roadside ditch; paramilitary forces who made camp in the village refused to allow any to be retrieved for burial.

"I have no guarantees that I or my four sons will be safe if I go back," said Luis Alberto Ganas, a farmer who fled from the hamlet of La Paz, a few hours from Naya. "The government needs to find some way to help us, because I can tell you, there will be more people like me on their way."

Naya, a town of 8,000, became a target because of its vast coca fields and location along a strategic stretch of river used by guerrillas to transport guns from the Pacific Ocean. The National Liberation Army, or ELN, also used the thick jungle around Naya as a hiding place for kidnap victims.

Last month, a commission consisting of the United Nations, the ombudsman's office and the Interior Ministry warned the government that Naya was ripe for a paramilitary strike, placing it on a long list of Colombian towns under threat at any given moment. An overstretched army made no move to protect it, human rights groups say, and has yet to secure the region, where more than 150 families are still missing.

Paramilitary commanders in the region, wary of public relations fallout from the killings, say their troops are required to conduct assassinations with single shots to the head. They have dismissed the more grisly accounts from Naya as fiction based on postmortem mutilations done by guerrilla forces. But Vasquez said that for at least 10 victims recovered so far, a machete blow was the cause of death, not an afterthought.

In an interview last month, Carlos Castano, the AUC commander in chief, pledged to turn himself in if it were proven that his troops carry out killings in such ways. But he also warned that, because his 8,000-member militia is growing exponentially, "excesses" might result from a lack of properly trained field commanders.

For years, Naya and the surrounding region, populated by mostly black and indigenous people, has been home to a large guerrilla presence. The ELN and the larger rebel group, the Revolutionary Armed Forces of Colombia (FARC), operate there, and the two guerrilla forces have now joined forces to confront paramilitary troops. New coca crops in and around Naya have given the guerrillas and the paramilitary fighters a financial incentive to control the region in order to tax the drug trade.

Delio Chate, a 41-year-old farmer who has a 25-acre coca field near Naya, said the killing started on April 11. Paramilitary troops rounded up Naya residents, house by house, and assembled them along the dirt path running into town. Chate said the paramilitary commanders gave his neighbors two chances to answer: "Do you know any guerrillas?" A machete blow followed the third negative response.

Chate, now living in a second-grade classroom, said the schedule was the same for three days. He saw neighbors die by the handful, and he said some were alive and some dead when paramilitary troops used a chain saw on their bodies. He escaped with his wife and two sons in darkness.

"Now, of course, the army is there or is trying to get there," Chate said. "But they left us out there alone."

Soldiers in Timba, Colombia, carry the body of a peasant, one of at least 40 people killed during last week's rampage.Rosalba Torijano looks on in horror as authorities try to identify those massacred near the village of Naya.