Laércio Guajajara said the men — who when not hunting are Forest Guardians protecting the Arariboia indigenous area — heard a noise in the forest coming toward the water.
"Hey Paulo, the game is coming, the peccaries are coming close," he said he whispered to his cousin and childhood friend, speaking in an interview for the documentary "Iwazayzar - Guardioes da Natureza." The filmmakers shared the video with The Associated Press.
They got low and waited. What emerged from the bush, according to Guajajara, wasn't a group of animals, but rather five men firing their guns in an ambush by illegal loggers that left one guardian dead and another injured. State authorities said a logger was also killed.
The deadly ambush late Friday in Brazil's Maranhao state is only the most-recent demonstration of how indigenous people are increasingly vulnerable to incursions by loggers and cattle ranchers, particularly in remote areas of the Amazon that receive little state oversight.
Speaking Saturday after leaving the hospital in the city of Imperatriz, Laércio said he was struck on his arm and back. He turned to his longtime companion only to find Paulo had already fallen to the ground, shot in the neck. Paulo Paulino Guajajara, 26, was dead.
Laércio bolted. He reckons he ran 6 miles (10 kilometers) before he found help, he said in the video. He said the men had heard loggers in the area the prior day, but the men never expected to be ambushed.
Forest Guardians had previously received threats and wore protective vests while on patrol. Still, Paulo's father Zé Maria Paulino Guajajara said during his eulogy on Sunday that he never imagined his son would meet this end. He spoke through tears in front of the mound of earth covering Paulo's body. Small white candles poked from its surface.
"My son fought and died. He died for all of us here, defending this area," he said.
Video from the funeral shows his wife simultaneously singing and crying, at one point falling to her knees on the candlelit hut's earthen floor.
Concern about the rainforest has heightened after Brazilian President Jair Bolsonaro took office this year with calls to loosen protections for nature reserves and indigenous lands. Fires used to clear land in the Amazon increased sharply in July and August, causing international alarm over a region seen as critical to curbing climate change.
Bolsonaro has said some economic development is necessary in the Amazon.
His government deployed federal police to investigate the killing. Brazil's justice and public security minister, Sergio Moro, said on Twitter they will "bring those responsible for this crime to justice."
No arrests have yet been made in the case.
Laércio, for his part, doesn't expect justice. He says he will continue to fight "as long as I have life, as long as I have strength to pull a bow and arrow or lift a club."
"We're not going to desist from this war. It's the protection for our future generations," Laércio said. "If we don't fight, even losing a lot of warriors, what will be there for our kids in 20 years? 30 years? What will become of the forest?"