More than 200 Indigenous artists and Hollywood celebrities pleaded with President Joe Biden on Thursday to grant clemency to Leonard Peltier, the ailing 78-year-old Native American rights activist whom the U.S. government put in prison 47 years ago after a trial rife with misconduct, lies and racism.

We write to you today in support of Leonard Peltiers petition for executive clemency and urge you to expeditiously commute the remainder of his sentence, reads the letter to the president led by six Indigenous actors, writers and fashion professionals. Nothing is more emblematic of the mistreatment of American Indians and the uneven hand of the criminal justice system than the handling of his case by the federal government.

The letter, first obtained by HuffPost, warns that Peltier is elderly and in failing health, and we fear he will not ever make it back to his homelands at Turtle Mountain in North Dakota.

Leonard is not only a symbol of Indigenous pride, he is also our relative. And his homecoming is imperative to our collective healing, they added.

The letter was spearheaded by Indigenous artists Dallas Goldtooth, Bird Runningwater, Jana Schmieding, Sierra Teller Ornelas, DPharaoh Woon-A-Tai and Bethany Yellowtail. Some of the non-Indigenous allies who signed the letter include actors and artists Mark Ruffalo, Ani DiFranco, Ed Helms, America Ferrera, Jackson Browne, Michael Moore, Bonnie Raitt, Ringo Starr, Tanya Tucker and Steven Van Zandt.

Heres a copy of their letter:

Many consider Peltier to be Americas longest-serving political prisoner . Hes been in prison since 1975, when the FBI and U.S. Attorneys Office convicted him of murdering two FBI agents during a shootout on Pine Ridge Reservation in South Dakota.

But the U.S. government never had evidence that Peltier committed a crime, and the level of misconduct that went on in his trial is baffling: Prosecutors hid exculpatory evidence. The FBI threatened and coerced witnesses into lying. A juror admitted she was biased against Peltiers race on the second day of the trial but was allowed to stay on anyway. His co-defendants were acquitted on self-defense grounds, but Peltier was singled out for different treatment.

It didnt get any fairer once he was in prison. His decadeslong parole process has been so problematic that United Nations legal experts recently reviewed his case and, over the summer, called on Biden to release him immediately. The working group concluded in a damning 17-page legal opinion: Mr. Peltier continues to be detained because he is Native American.