The case of murdered nun and activist Dorothy Stang has brought into sharp focus the vigilante violence that accompanies the destruction of Brazil's rainforest.
On first appearance, Dorothy Stang - who was 71 when I met her - looked very much the little old lady, as she welcomed us into her small house.
Dorothy Stang campaigned in the Amazon for 30 years
She had snow-white hair, large glasses, red cheeks and a large smile.
But there was also a glint in her eye which suggested convictions and commitment, great strength.
As soon as I sat down she looked straight at me and asked in her quiet voice: "So, whose side are you on?"
Sister Dorothy had no doubt about her place in the battle-lines drawn over the future of the Amazon.
She was, she said, for the interests of the huge majority of poor Brazilians who live there.
Sometimes, almost in a whisper, she talked passionately about 30 years she had spent trying to improve the lives of penniless settlers moving into the Amazon, teaching them to live with the forest rather than destroy it.
She described the logging companies coming to the remote town of Anapu where she lived, cutting down the forest illegally. And she talked about corruption.
This was the story I was investigating.
Some of the most powerful politicians from the Amazon state of Para were being prosecuted by the federal government, accused of stealing more than $1.8m (£1m) of development money.
They had been setting up farming projects with the main purpose, prosecutors concluded, of pocketing generous federal grants.
The federal prosecutors suggested we talk to Sister Dorothy, one of their sources of information on the ground.
So we travelled to Anapu, which took two plane rides and a day's drive down the unpaved Pan-Amazon highway.
I remember the shock of a landscape with hardly a tree in sight, not what I had expected in the middle of the world's largest forest.
Around Anapu we saw where some of the money intended for development had been going.
Cattle ranches where there were no cattle, coffee plantations with no coffee, and fruit farms with no fruit trees.
What angered Sister Dorothy most was that all the development money had gone to big farming projects, rather than to help the hundreds of thousands of small settlers in the region.
It was extremely hot. Sister Dorothy had said the climate was changing.
The dry season was lasting longer, the water table was dropping and it was too hot for people to work through the day.
In taped confessions her killers described the execution-style killing
Many of those we talked to were worried about vigilante violence.
More than 500 peasant leaders and other activists had been killed in the Amazon state of Para in the previous two decades, and almost no-one had been brought to justice.
Sister Dorothy had herself received death threats. She was murdered this February.
In videotaped confessions to the police her two killers described shooting her execution-style as she read her bible - although they gave different versions in court. One of them said he shot in self defence after confusing her bible for a gun.
Prosecutors hope the convictions of the gunmen will open the way for three other men, two of them landowners, to be tried for allegedly offering more than almost $18,000 (almost £10,000) for Dorothy Stang's murder.
Human rights groups see this as a key test as to whether Brazil can stop the vigilante violence which goes hand in hand with the destruction of the forest.
I have always regretted we did not film Sister Dorothy. She didn't want to.
Not because of the danger, rather as a North American, she did not want to antagonise Brazilian nationalist feelings.
Human activity has wiped out large areas of the Amazon rainforest
This is a sensitive area. Since meeting Sister Dorothy I have several times been subjected to harangues from angry ranchers and loggers that foreign interests are trying to steal the Amazon.
Groups like Greenpeace and the World Wildlife Fund, the argument goes, are forcing the government to set up reserves as part of a conspiracy to stop Brazil from developing.
Shortly after Sister Dorothy's murder, one wealthy landowner I interviewed talked about her as a dangerous foreign agitator.
Ironically, those who argue this the strongest are people whose wealth comes from selling wood or cash crops to multinationals for export.
As Dorothy Stang never tired of pointing out, and as more and more Brazilians are now arguing, destruction of the Amazon on today's scale is clearly not in Brazil's long-term national interest.
Her commitment reminded me strongly of Jesuits of Spanish origin I met working with peasant communities in the civil war in El Salvador in the 1980s. Several of those were murdered by a military death squad.
One of them told me once how he had been confronted by a young army officer who said that as a foreigner he should not be there.
"But I am more Salvadoran than you," the priest replied. "First, by the look of your age, I've been here longer. More importantly," he said, "you were born Salvadoran by chance. I chose this country."
In Brazil, the same was true of Sister Dorothy.
From Our Own Correspondent was broadcast on Thursday, 15 December, 2005, at 1100 GMT on BBC Radio 4. Please check the programme schedules for World Service transmission times.