The man accused of killing American nun and rain forest defender Dorothy Stang told a jury Friday that he acted in self-defense after mistaking her Bible for a gun. Rayfran das Neves Sales is accused of killing Stang, 73, with six shots from a .38-caliber revolver on Feb. 12 on a muddy road deep in the heart of the Amazon rain forest.

Sales testified he and Stang had an argument over who owned the land he was working, and that Stang threatened to "finish him off" with the help of some 150 people living on a sustainable development reserve she was trying to establish.

"She said, 'The weapon I have is this,' and reached into her bag," Sales said. "I didn't know what she was going to pull out of her bag so I shot her."

Prosecutors allege that rancher Vitalmiro Moura offered Sales and co-defendant Clodoaldo Carlos Batista $25,000 to kill the nun, who spent the last 30 years of her life defending poor settlers in the rain forest. The prosecution contends that she was reading her Bible when she was shot at close range.

In his testimony Friday, Sales sought to remove blame from his co-defendant and from Moura, one of two ranchers accused of orchestrating the killing.

Sales acknowledged that his employer, Amair Feijoli, had given him the gun and told him to kill the nun a day earlier. But Sales denied being offered money to kill her.

Feijoli has been charged with acting as a go-between for the gunmen and ranchers.

A Brazilian Senate commission found the killing was part of a wider conspiracy involving a number of ranchers. Only Moura and rancher Regivaldo Galvao have been charged with orchestrating the shooting.

Sales said Friday that he didn't intend to kill Stang but that after firing the first shot he "lost his head." He didn't remember firing five more bullets, he said. He said Batista didn't know Sales had a gun and ran when the first shot was fired.

After the killing, Sales said, he met Batista in the forest and the two men fled to a house owned by Moura, who was shocked to learn what had happened.

"He said he wouldn't wish that on his worst enemy much less Dorothy," Sales said.

Sales' testimony contradicted earlier confessions and seemed to be part of a defense strategy to classify the crime as a "simple homicide," which carries a lesser sentence than a premeditated hit.

Stang, who was born in Dayton, Ohio, has evoked comparisons to rain forest defender Chico Mendes, who was killed in 1988 in the western Amazon state of Acre. Human rights advocates and a United Nations observer are among those attending the trial in this Amazon port city.

"If they are convicted it would be a sign that things are changing and impunity is ending," said Sandra Carvalho of the human rights group Global Justice.

Stang's brother traveled from his home near Cold Springs, Colo., to attend the trial. He called Sales' testimony absurd.

"It's lies, all lies," David Stang said.

Outside the courthouse, some 500 protesters camped out under crude tarpaulins, waving banners demanding justice and land reform.

Stang was killed in Para state, which is notorious across Brazil for corruption and land-related violence that in the past 20 years has claimed the lives of some 534 people. Only eight killers ever have been convicted.

Rural violence has claimed nearly 1,000 lives in the past decade in Brazil.