Federal police surrounding the Roosevelt Indian Reserve in Brazil's Amazon rain forest have developed a list of 12 Cinta Larga Indians they say took part in the massacre of 29 diamond miners last month.
But the suspects may never face jail time. Under the Brazilian Constitution, Indians from isolated communities can be judged incapable of understanding the law and are thus immune from responsibility for breaking it.
The fact that killers may go unpunished has rekindled debate here over indigenous rights. The same laws that grant immunity to Indians also relegates them to second-class citizenship. Observers say it's time that native Brazilians be given the same rights - and have the same responsibilities - as the rest of the country's population.
"It's what we call ... a [Trojan] horse," says anthropologist Alcida Ramos, referring to the law that keeps Indians immune from prosecution but also makes them wards of the state. "Yes, it affords protection in a few situations, but minority status also denies them many of the rights of other Brazilians."
Since the April 7 massacre, federal law-enforcement officials, supported by the Brazilian Army and Air Force, have kept the reserve - 575,000 acres of isolated, pristine rain forest in the state of Rondônia - under a virtual siege. Checkpoints have been installed at all access roads and navigable rivers out of the reserve.
The Cinta Larga territory is said to contain one of South America's richest diamond deposits. Mechanized mineral extraction is illegal on Indian territory in Brazil, but since diamonds were discovered in 2000, thousands of miners have flooded Cinta Larga lands, despite sporadic attempts by federal police and the Brazilian Federal Indian Agency (FUNAI) to have them removed.
In 2003, the Cinta Larga themselves began mining in defiance of Brazilian law, often with technical assistance from non-Indian miners. Disputes over the mining proceeds have been common, and according to federal police may have been at the root of the April 7 killings.
The agents assigned to the case have interviewed dozens of miners who survived the attack, using their testimony to compile the suspect list. Police say they have so far avoided entering tribal territory to apprehend suspects, both to prevent further conflict with the Cinta Larga and to preclude a manhunt in the vast and inhospitable rain forest.
"What we would like is for them to turn themselves over," says Marcos Aurélio Moura, federal police superintendent, who has been negotiating with the Cinta Larga through intermediaries from FUNAI.
But once suspects are in custody, obtaining convictions could be complicated by the Brazilian Constitutional and criminal code, even if police and federal prosecutors determine there is enough evidence to press charges.
Under a 1993 legal reform, says FUNAI official Luiz Soares, isolated peoples can have immunity from prosecution. The determination is made by a criminal-court judge, with the aid of a professional anthropologist, using criteria such as the accused's ability to speak Portuguese - the official language of Brazil - and his degree of exposure to Brazilian culture and society.
The Cinta Larga tribe only came into contact with the outside world in the 1960s. The tribe numbers about 1,300 individuals, about half of whom speak Portuguese. According to Mr. Soares, the Cinta Larga's relative isolation argues in favor of their immunity, in the event that a tribal member does get charged.
"It's a right they have under Brazilian law, and I would certainly push to see that they make use of that right," he says.
Expanded indigenous rights swept through South America the 1990s. New constitutions were enshrined in Colombia in 1991, Peru in 1993, Bolivia in 1994, and Ecuador in 1997.
In varying degrees, these new constitutions all give aboriginals more rights over land and provide some recognition of communal ownership of resources. But only Brazil allows for the lenient treatment of Indians in criminal proceedings.
And here there are significant drawbacks to Indians' special status. It has prevented them from entering into contracts, starting businesses, and in many cases even exercising control over their traditional lands and resources, says Ms. Ramos. Instead, the resources of Brazilian Indians are often put under the management of FUNAI.
"On balance, I would say minority status has not served Brazil's Indians well," says Ms. Ramos.
The potential immunity from prosecution for the killings has engendered a backlash. In Espigão d'Oeste, the town closest to the Cinta Larga reserve, one Indian was taken hostage by angry miners in the days after the massacre. The man was freed only after police intervened. The rest of the town's small Indian population has since fled back to the forest, according to mayor Lucia Tereza Santos.
Indian immunity has long aroused resentment among rural people in Brazil, particularly in the mining industries. Visitors to the Brazilian interior are often told by locals to steer clear of Indian land. Indians have been known to hold visitors for ransom or arbitrarily confiscate their belongings, they say.
Immunity, however, is not a given. It is usually refused by judges, according to Soares. Attempts to set up parallel tribunals to judge Indians according to their own tribal laws and traditions have so far proved too controversial, he says.
Once the government removes its cordon around the Cinta Larga lands, Ms. Santos says the miners will return, and the illegal mining will resume, rekindling tensions.
The way to bring peace to the region, she says, is to give the Cinta Larga the legal right to mine on their territory, then regulate and control it. Under the Brazilian Constitution, however, the only way to give the Cinta Larga the right to mine would be through the passage of a special act of congress.