A federal appeals court is being asked to order a hearing for an 88-year-old federal prisoner who's trying to erase his conviction because he says the alleged child victims in a sexual assault case have recanted their testimony from 16 years ago.

Douglas White, an American Indian spiritual leader from the Pine Ridge Indian Reservation, is imprisoned in Minnesota. His sentence ends in February 2014. His lawyer says White has cancer and is in failing health.

Central in the legal case is when White knew of the recants.

There's a one-year window to seek post-conviction relief in court after obtaining what is considered new information.

White's life and case is the subject of a documentary film written and directed by a New York couple and narrated by actor Martin Sheen.