Leonard Peltier, who has been described as a “remorseless killer” after being convicted of killing two FBI agents on a South Dakota reservation, was released after nearly five decades in prison after being granted clemency by former President Biden during one of his final acts while in office.

The 80-year-old Peltier was released on Tuesday from a federal prison in Florida and is expected to attend a welcome home party at a reservation casino with supporters celebrating his release from what they call a “wrongful incarceration,” according to a report from NBC News.

“We made a commitment to free Leonard Peltier and bring him back to his homelands — this is us fulfilling that commitment,” Founder and CEO of Indigenous peoples organization NDN Collective, Nick Tilsen, said in a statement. “We are welcoming Leonard back home in a beautiful way to thank him for his legacy by feeding the people, thanking everyone who fought for him for years, and honoring those who fought for his freedom but are no longer with us.”

The decision to grant Peltier clemency came on President Biden’s final day in office and was instantly condemned by law enforcement officials.

“Mr. President, I urge you in the strongest terms possible: Do not pardon Leonard Peltier or cut his sentence short,” then-FBI Director Christopher Wray wrote to President Biden in early January as he mulled over a decision. 

“Peltier’s claims are meritless. And his convictions and sentence must stand. Even though courts have repeatedly examined and exposed Peltier’s claims as baseless, his sympathizers continue to wrongly promote him as a standard-bearer for legitimate grievances about the United States government’s historical mistreatment of Native Americans.”

“But the facts cannot–and must not–be ignored. Peltier is a ruthless murderer who has shown a complete lack of remorse for his many crimes.”

Peltier, a long-time activist, was convicted in June 1975 after a shootout that left FBI agents Ronald Williams and Jack Coler dead after they had entered the Pine Ridge Indian reservation to search for a suspect in the assault of two local ranch hands.

Peltier, who was a member of the American Indian Movement and a fugitive from the law at the time for the attempted murder of a Wisconsin police officer, has long maintained his innocence while serving two life sentences over the past 50 years, claiming that he has been a political prisoner, which many of his democratic supporters and other political activists have embraced.

He has received support over the years from Coretta Scott King, Pope Francis, and the Dalai Lama, as well as numerous celebrities and lawmakers in Washington.