A member of a protected tribe in the Amazon has been killed by gunmen, authorities in the Brazilian state of Maranhao say.
The body of Zezico Guajajara, of the Guajajara tribe, was found near his village on Tuesday. He had been shot.
The former teacher was a supporter of Guardians of the Forest, a group formed to combat logging gangs in the area.
The killing - the fifth in six months - increases concerns about violence against Amazon forest protectors.
Brazil's populist President Jair Bolsonaro has drawn intense domestic and international criticism for failing to protect the Guardians' territory in the eastern Amazon region.
He has often stated support for farmers and loggers working in the area, while criticising environmental campaigners and slashing the budget of Brazil's environmental agency.
The Guajajaras are one of Brazil's largest indigenous groups with some 20,000 people. In 2012, they started the Guardians of the Forest to protect the Arariboia Indigenous Territory.
It is not clear who killed Zezico Guajajara on Tuesday. Authorities say they are investigating.
In a statement issued on Wednesday, indigenous leader Olimpio Guajajara described him as "another fellow warrior - a man who defended life".
"We are mourning his death. We're protecting the forest for all humanity, but powerful forces are out to kill us."
The Brazilian Indigenous Peoples' Association (APIB) urged a thorough investigation.
The latest murder "is evidence of the worsening violence and vulnerability of the indigenous people, especially the leaders that fight to defend their territories against invaders," the group said in a statement.
Sarah Shenker, who works for Survival International, a non-governmental organisation advocating for indigenous communities, accused loggers of targeting activists "one by one".
The group renewed its criticism of President Bolsonaro.
"The Guardians have been mercilessly targeted by powerful logging mafias illegally exploiting the valuable hardwoods in the Arariboia indigenous territory, home to both the Guajajara indigenous people and uncontacted members of the Awa tribe," it said in a statement.