The gunmen arrived in the Amazon dusk, circling the house where Sister Leonora was hiding, rifles and pistols poking out the windows of three muddy pickup trucks. A violent death was meant for the diminutive 64-year-old Roman Catholic nun, who has spent decades defending poor, landless workers -- and collecting countless threats from ranchers she blocked from stealing Amazon land. Leonora Brunetto faced the fate of Brazil's renowned rain forest protector Chico Mendes and American nun Dorothy Stang, whose accused killer is scheduled for retrial Wednesday in the jungle city of Belem. But before the gunmen could put her among the 1,200 activists, small farmers, judges, priests and others killed over preserving the rain forest since Mendes' murder in 1988, a car full of landless workers pulled up to defend Brunetto. The gunmen left, opting to take their shot at the gray-haired woman another day. One of those who came to her rescue, though, was shot dead the next afternoon. As in many of the cases, his killer still walks free. Impunity in the Amazon because of a weak judicial system and corruption among local officials is endemic, a problem not only for people like Brunetto, but for the Brazilian government trying to preserve a rain forest the size of the U.S. west of the Mississippi. More than 20 percent of the forest already has been destroyed. Rancher Vitalmiro Moura, who is accused of ordering Stang's murder in 2005, served three years in prison before being acquitted in a retrial. Now prosecutors are trying to get a conviction again in a third trial, which his defense team is seeking to delay. Among hundreds of cases of activist killings, Moura is the only accused mastermind imprisoned while he awaits retrial, according to the Catholic Land Pastoral, a watchdog group that tracks rural violence in Latin America's largest nation. He has said he had nothing to do with Stang's killing and had no involvement with the land dispute that led to her death. Stang prosecutor Edson Souza said bringing killers to justice and stopping the bloodshed is the only way Brazil will halt the destruction of the jungle. 'Without a doubt, leaders like Dorothy are targeted,' Souza said. 'If they get away with killing leaders like Dorothy, the poor rightly assume they could easily be murdered as well.' The main cause of deforestation, the government says, are ranchers who illegally clear jungle to graze cattle and grow soy -- often using threats and violence to remove the poor farmers eking a living there. The Brazilian government aims to give land titles to poor farmers, who some argue are less destructive to the forests because they have small plots and do less clearing. But the process has required people like Stang and Brunetto, who help locals stand up to intimidation against their claims on unused land. The episode in 2007 of gunmen circling Brunetto's safe house was just one of many brushes with death she recounted as she showed The Associated Press around an area of Mato Grosso state where she works, raising the spirits of those who camp on unused property and wait years for titles. A Brazilian who studied to join the convent from age 12, Brunetto used to travel only with armed military police. But she has stopped. 'I have many friends under death threats, but they have no protection,' she said. 'How can I lead people if I have protection and they don't? Besides, it's the people who protect me most.' Mato Grosso -- 'thick jungle' in Portuguese -- was once rain forest but is now the breadbasket of Brazil with its vast soy plantations and cattle ranches. The ranchers and farmers who rule the state live well, employing legions of landless farmworkers for a pittance. Those workers face hunger and disease in makeshift shelters built from scrap wood and black plastic, with no electricity or running water. 'A few with much, and many with so little,' Brunetto said. She spoke at a dusty camp of squatters, who live at the edge of a local farmer's land they say is unproductive -- and thus, according to Brazil's constitution, available for redistribution. 'How can you fold your arms in front of this injustice? I can't.' Brunetto, 5 feet (1.5 meters) tall and 110 pounds (50 kilograms), walks through the camps in jeans and leather sandals, firmly shaking hands and giving hugs. She patiently listens as a shirtless man tells her about hothouse-grown plants residents sell for 50 cents each, then turns to a nearly toothless woman who worries about getting enough food to eat. The squatters are star-struck. 'Sister Leonora is a warrior for the people,' said Linda Maria de Jesus, a 59-year-old camp resident who was on the verge of tears at seeing Brunetto. 'She is threatened; she is in a battle just like us. It raises our spirits to have her here.' Brunetto is rarely out of the watchful gaze of one hulking -- though unarmed -- poor farmer or another. They pick her up at bus stations, drive her 100 miles (160 kilometers) then hand her off like a sacred package to another rural worker, who will take her on to her destination. She meets with local, state and federal officials to press the numerous cases of small farmers fighting for land. She helps impoverished, illiterate people work their way through the onerous process of winning a title to a piece of property. 'I'm always looking over my shoulder wherever I go,' Brunetto said after offering the squatters praise for their makeshift plant nursery. Souza, the prosecutor, has seen numerous killers walk free in neighboring Para, the Amazon region's most violent state, where the 73-year-old Stang was gunned down on a muddy dirt road. He argues she was ordered killed by Moura and fellow rancher Regivaldo Galvao because she was blocking them from obtaining land the government had given to a group of poor farmers. The confessed gunman who shot her is serving a 27-year sentence in prison. Two other men were convicted as accomplices in 2005 and given 17-year sentences. Galvao has managed to remain free -- but is scheduled to go to trial at the end of April. Brazil is trying to bring law to the Amazon, mostly through increased environmental agent patrols the government says resulted in the lowest recorded levels of deforestation in 2009. What remains to be seen is what can be done to protect those protecting the forest. 'I cannot lie and say I'm not scared,' Brunetto said. 'But at the same time I know God is with us. My two great protections are God and these people we help.' 