Sen. Bernie Sanders (I-Vt.) strongly supports releasing Native American rights activist Leonard Peltier from prison, according to a letter to a constituent obtained by HuffPost.

As you know, Leonard Peltier has spent over 40 years of his life in prison despite the fact that the government has admitted they do not know who is responsible for the crime he was convicted of, Sanders said in the June 8 email. Despite national and international campaigns to free Peltier, he remains incarcerated, where he continues to advocate for the rights of native peoples.

For this reason, I have and will continue to strongly support petitions for Leonard Peltiers release, Sanders concludes.

A constituent passed the letter to HuffPost. A Sanders spokesperson confirmed its legitimacy, but did not provide further comment on the senators views on Peltiers imprisonment.

The letter means that Sanders is the fourth U.S. senator in recent months to advocate for President Joe Biden to give clemency to the now-77-year-old, ailing activist and send him home. Sens. Patrick Leahy (D-Vt.) , Brian Schatz (D-Hawaii) and Mazie Hirono (D-Hawaii) have separately and publicly called on Biden to release Peltier.