BRISTOL, R.I. (AP) -- There's an early scene in Tony Goldwyn's "Conviction" when law student Betty Anne Waters offers a textbook definition of "contract" for her classmates.
It foretells the contract the real-life Waters had with her brother Kenny Waters: He would keep himself alive in prison, where he spent 18 years on a murder conviction, in exchange for his sister laboring through law school with the singular goal of establishing his innocence.
When she finally -- and improbably -- did, it wasn't long before Hollywood saw a movie in the story.
The result is "Conviction," with Hilary Swank in the role of Waters -- a Rhode Island woman who put herself through college and then law school before using DNA evidence from the murder scene to exonerate her brother and win his release in 2001.
"The truth -- you couldn't make it up," Goldwyn says of the Waters' story.
The Fox Searchlight film, shot in Michigan and New England on a $12.5 million budget, premiered last month at the Toronto International Film Festival and opens nationwide on Oct. 15.
Swank, who won two best actress Academy Awards for 1999's "Boys Don't Cry" and 2004's "Million Dollar Baby," was given the script while training for the latter film. She said she was inspired by Waters' devotion to her brother but also horrified that an innocent man had spent nearly half his life in prison for a crime he didn't commit.
"There's a part of you that has to be like, 'This could never happen"' to an innocent person, she said in an interview from Los Angeles. "And then you realize that it is happening."
Betty Anne Waters was a young mother in 1982 when her older brother was arrested and charged in the brutal slaying and robbery of his neighbor, Katharina Brow, in Ayer, Mass., two years earlier.
Despite an alibi that placed him at a diner and in court on the morning of the killing, a jury convicted him of murder, largely on the strength of witnesses -- including an ex-girlfriend -- who later recanted their testimonies. Bloody fingerprints found at the scene were never presented as evidence at the trial, nor was his time card from work.
Kenny Waters (portrayed by Sam Rockwell) was a fun-loving rabble-rouser with a hair-trigger temper, capable of cursing at cops, dancing nude in goofy sunglasses and knocking out a man in a bar fight and then offering him a splash of Wild Turkey.
"The truth is, he was volatile," Rockwell said in an interview. "He had a temper, but he also was a very charming guy and from what I heard, he was very childlike. He was a complicated guy."
Facing a life sentence following his 1983 conviction, Kenny Waters attempted suicide. His appeals exhausted, he told his sister the only way he could sustain hope, the only path for him to remain alive, was if she could somehow become a lawyer and exonerate him.
Never mind that his sister had no money and only a GED at the time, and that he had little trust in a legal system he felt had wronged him.
"Kenny had more faith in me than I could ever have in myself -- ever -- all my life," Betty Anne Waters said in an interview at Aidan's, an Irish pub in Bristol, R.I., that she continues to co-manage. "It wasn't the first time he thought, 'Betty Anne can do anything.' He always thought I could do anything."
She took community college courses and then earned a degree at Rhode Island College before enrolling in law school at Roger Williams University in Bristol and graduating in 1998 -- an education she just finished paying off two years ago.
She earned extra cash through her work at Aidan's, and even as she slogged through traditional law school classes for which she had no practical use, she focused on her brother's case and grew fascinated by the still-emerging field of DNA testing.
After law school, she discovered a box of forgotten evidence at the courthouse. She worked with the Innocence Project, which operates to free wrongfully convicted prisoners, and attorney Barry Scheck to preserve the evidence and have the blood tested against Kenny's DNA.
The results didn't match, Kenny Waters was released and prosecutors vacated the conviction in 2001. Last year, the town of Ayer and several insurers reached a multimillion-dollar settlement over the handling of the case, which remains unsolved.
Despite her legal fame, the 56-year-old Betty Anne Waters does not actively practice law, but still works on cases with the Innocence Project.
Goldwyn said he learned about the case from his wife, who told him excitedly about a TV special she had seen. He was moved by Waters' perseverance, but also wondered what would have happened had she been wrong. What if her brother turned out to have been guilty or what if, despite her best efforts, she couldn't spring him from prison? Would her crusade have been somehow futile?
"To me, the answer was no, because this bond she had with her brother -- to me -- is what life is all about," said Goldwyn.
The film, written by Pamela Gray, is largely factual but takes some liberties in the chronology of events. It suggests Kenny Waters languished behind bars well after the DNA results came back, though he walked out of prison just two weeks after being ruled out as the killer.
The movie also omits his death at age 48 of head injuries from a fall, six months after his release. Goldwyn said he considered including the death, but decided it didn't fit.
Betty Anne Waters was ambivalent about the attention, but her brother was thrilled with the nonstop calls they received after news got out of his release from prison.
"'I'm answering it -- it's probably Hollywood calling again,"' Betty Anne said of Kenny's reaction. "He loved it, and he's like, 'Betty Anne, you have to do this movie."'