An 88-year-old convicted sex offender has asked a court to vacate his 1993 conviction because the two men he was accused of molesting as children recanted their testimony.

Douglas White, an American Indian spiritual leader from the Pine Ridge Indian Reservation, has asked the 8th U.S. Circuit Court of Appeals to order a re-examination of his 1993 aggravated sexual abuse conviction. White was accused of molesting two young boys, and the appeals court later upheld his conviction and sentence of more than 24 years in federal prison.

White sought to have his case reheard, but U.S. District Judge Richard Battey ruled that White missed his one-year window after the first witness recanted his testimony.

White's attorney, Terry Pechota of Rapid City, argues that White couldn't have succeeded in getting his sentence overturned until both witnesses recanted, and that White filed his papers within one year of the second witness recanting in December 2007.

Pechota wants the appeals court to instruct Battey to rehear the case. White, who is scheduled for release in February 2014, has cancer, Pechota said.

Mark Salter, an assistant U.S. attorney in Sioux Falls, said his office does not comment on pending cases.

White, who oversaw religious ceremonies for fellow Oglala Sioux Tribe members, is the subject of a documentary, "Holy Man," that is scheduled for release later this year. Written and directed by a New York couple, Jennifer Jessum and Simon Joseph, and narrated by Martin Sheen, the film follows White's case and his life behind bars.

Jessum said she and her husband met White in 1992 before the indictment and visited him frequently after the conviction when he was in a Denver prison.

"Our interest in this started very innocently. We just thought, wow, here's this gem really for the tribe and for our country because this guy is in his 80s, he speaks this ancient language, really doesn't know the Western world, is very much entrenched in his Lakota traditional world and we just wanted to film him, to kind of preserve him for the tribe and for everybody because he was such a fascinating person," she said.

The documentary was finished a year ago but will be updated and released later this year, Jessum said.

"We decided to just sort of keep it on hold until Douglas' case went through the system because we were convinced from all the evidence that we would have a new ending of Douglas getting out of prison."