Phillips and Pereira vanished on June 5, 2022 on a trip to the remote Javari Valley near the border with Peru. Days later, a fisherman who had confronted Indigenous patrols in the area confessed to killing them.
"This rally reaffirms our commitment to preserving Dom's purpose. We cannot let that be forgotten," Phillips' brother-in-law Marcus Sampaio told reporters at an event on Copacabana Beach in Rio de Janeiro.
Police have said the alleged leader of a local gang planned the murders because Pereira posed a threat to its illegal fishing operation.
During an event for the presentation of measures to tackle deforestation in Brazil, President Luiz Inacio Lula da Silva said the best way to honor them was to ensure "their struggle has not been in vain." He said their murders "shocked the world" and made many realize the Amazon was "a land without law and on the verge of destruction."
Phillips, a freelancer for the Guardian, the Washington Post and other media, had been working with a group of journalists to complete a book about saving the Amazon when he was killed at age 57.
Brazilian officials promised to uphold Phillips' and Pereira's legacies, with Indigenous Affairs Minister Sonia Guajajara saying Lula's government was "united in defense of nature and the rights of Indigenous Peoples."
Some are urging the government to do more to protect the Javari Valley, where drug runners and illegal poachers threaten the most isolated Indigenous groups in Brazil's Amazon.
"Nothing has changed there. The factors that caused that sad moment are still there," said Indigenous leader Beto Marubo, a friend of Pereira, a former official of government agency Funai who was 41 when killed.
(Reporting by Pilar Olivares; Writing by Gabriel Araujo; Editing by Angus MacSwan and Richard Chang)
