SAN JUAN, Puerto Rico (AP) — Brooklyn Rivera, a renowned Indigenous leader from Nicaragua who spent years fighting for the rights of his community and was imprisoned by the government in September 2023, has died.

The Nicaraguan government issued a statement Sunday saying that Rivera died from a bacterial infection after his health had declined following a case of COVID-19, which led to his physical and neurological deterioration.

Human rights activists and groups worldwide denounced his death and an earlier statement by the government in which they referred to Rivera as "Brother" and said they were praying for him.

"They took him alive, and after refusing to tell his family, his lawyer, the world anything about his fate, then they call him brother," said Reed Brody, an American human rights lawyer and member of a group of U.N. experts on Nicaragua. "Unconscionable cynicism on the part of the government to make it seem like they were trying to help him."

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The U.S. had called for his release on Friday after the Nicaraguan government published photos of him in the hospital in critical condition.

"This is just complete neglect," said Manuel Orozco, director of the migration, remittances and development program at the Inter-American Dialogue. "His death represents the magnitude of repression."

The Argentina-based Inter-American Center for Legal Assistance in Human Rights also denounced Rivera's death. Those responsible for the death of the Indigenous lawmaker "should be held criminally accountable," it wrote on X.

Albert R. Ramdin, secretary general of the Organization of American States, said he was "deeply concerned" about reports of Rivera's death.

"His death demands an immediate, independent, and transparent investigation," Ramdin wrote Sunday on X. "The rights to life, personal integrity, and due process must be guaranteed. My condolences to his family and the Miskito people. We continue to demand the unconditional release of all political prisoners unjustly detained by the Nicaraguan regime."

A fight for land and autonomy

Rivera led the Miskito people, who live along Nicaragua's northeast coast and have long fought to retain their lands.

For decades, he fought the ruling Sandinista government and helped establish the area along the northeast coast as an autonomous region. It is rich in gold, silver and other resources, and it is considered a key area for the administration of co-Presidents Daniel Ortega and his wife Rosario Murillo to attract foreign investment.

Rivera's fight for Nicaragua's Indigenous people began in the 1960s. After opposing Ortega's Sandinista's government in the late 1970s, he temporarily went into exile in nearby Costa Rica in 1980.

He later returned to Nicaragua, where he survived an attack by Sandinista forces, forcing him once again to seek safety elsewhere, this time, in Colombia.

In the late 1980s, he founded the group known as Yatama, the Organization of the Peoples of Mother Earth. It played a key role in securing limited autonomy for Indigenous people following peace negotiations with the Sandinistas.

"He has been fighting in one way or another for their rights," Brody said. "He fought for land, he fought for autonomy."

Nicaragua's Indigenous people operated autonomously until they were annexed into the country in 1905.

"Since then, they have advocated for the recognition of their rights and for respect for their identity," stated a September 2024 report published by the group of U.N. experts.

First official sign of life since the 2023 arrest

In April 2023, Rivera traveled to Geneva to participate in a U.N. forum on Indigenous people, where he spoke out against the Nicaraguan government.

Shortly afterward, Ortega and Murillo banned him from returning to the country, but he slipped in anyway and lived in hiding until September 2023, when he was arrested and accused of terrorism.

"Nobody heard from him since then," Brody said in a phone interview, adding that he and other U.N. experts wrote the government requesting that it provide some sign of life. "The government never gave any indication. He was a disappeared person."

It wasn't until late last week that the government published pictures of Rivera in the hospital.

Rivera was not only respected by his supporters, but by political opponents as well, Orozco said in a phone interview, noting he had known Rivera for decades.

"It's disheartening how this dynasty is just getting rid of people, back and forth, left and right and getting away with it," he said.

Ever since his arrest and that of his second-in-command, Rivera's party has gone into hiding, Orozco said.

"This is a big blow," he said. "They have been basically dispersed, not organized. They keep a certain level of communication, of political engagement underground, but mostly with people in the exile."

Condolences for Rivera poured in online, with one person writing on Facebook: "He was a father to our generation; he taught us, guided us, and led us with actions, not words."

Brody noted that the U.N. group of experts has documented 124 cases of arbitrary detention of Indigenous people in Nicaragua since 2018, and 46 deaths following violence incidents.

He noted that at least six political prisoners have died in custody since 2019, including two last August.

"Brooklyn Rivera spent 40 years fighting for his people," he said, "and hopefully the international community will finally pay attention."