Foxcatcher, starring Steve Carell as du Pont, tells the story largely from the perspective of Mark Schultz, David's brother and also an Olympic wrestler who lived at du Pont's farm at the time.
It drew raves - and the best-director prize for Bennett Miller - at the Cannes Film Festival in May, ensuring more attention from critics and filmgoers when it hits theaters here in November.
Nancy Schultz, who witnessed her husband's shooting, expects the film's release will be hard for her son and daughter, now 28 and 25. They have fond memories of living on the du Pont estate with other wrestlers' families. After screening the movie, it all came rushing back.
"They miss those days very much," she said from her home in San Carlos, Calif., south of San Francisco. "It really was an amazing place to be for most of the time that we were there. It was a wonderful life we had."
The second film, a documentary tentatively titled David, is headed by Nancy Schultz and filmmaker Jon Greenhalgh. It has been in the works since shortly after du Pont's 2010 death and includes interviews with friends, coaches, former teammates, and attorneys.
Nancy Schultz sees that project as a companion to Foxcatcher, and is seeking a distributor to release it around the same time .
She said that for her and her children, it was important to preserve as many memories of David Schultz as they could. Over time, they worried the sensationalism of the du Pont case would overshadow David Schultz's accomplishments, his contributions to the sport he loved, and the compassion that they say defined his character.
"A big part of me didn't want to create anything that would make du Pont more famous," she said. "But a lot of us also wanted Dave's story told."
Du Pont, who died at 72 in a Somerset County prison, was convicted of third-degree murder in 1997 after a trial that exposed his paranoia, drug use, delusional thinking, and bizarre behavior in the weeks before the shooting.
"Things were escalating," said one former prosecutor, Dennis McAndrews, now in private practice. "He was carrying a gun everywhere."
Du Pont's wealth as an heir to the chemical giant afforded him access to a top-shelf legal team and the best mental-health experts, McAndrews said. That army of lawyers built a defense intended to convince a jury that du Pont was not guilty by reason of insanity, which led to lengthy pretrial motions and arguments.
"Just fending off every one of those filings was a gargantuan task," said U.S. Rep. Pat Meehan, who was Delaware County district attorney at the time.
Experts for both sides testified that du Pont was mentally ill, but defense attorneys wanted the jury to find he was so delusional he did not know shooting Schultz was wrong.
Prosecutors suggested that du Pont, who had sponsored the Schultz brothers and the U.S. wrestling team by providing training facilities and housing, was motivated by jealousy over David Schultz's friendship with another wrestler.
Through interviews with witnesses and those in du Pont's inner circle, then-prosecutor Joseph McGettigan came to believe Schultz was one of the most positive influences in du Pont's life.
"Some of the people du Pont had around him by then maybe saw him as a meal ticket," said McGettigan, who returned to the spotlight in 2012 when he prosecuted serial child molester Jerry Sandusky. "But Dave was a truly altruistic person. He wanted to help him."
The jury found du Pont guilty but mentally ill - which ensured he would serve time in a psychiatric hospital. A judge sentenced him to 13 to 30 years in confinement.
Taras M. Wochok, du Pont's longtime attorney and one of several lawyers on his team, said the case gave him a greater understanding of the nuances of mental illness. Up to the end, he said, psychiatrists couldn't agree on whether du Pont suffered from paranoid schizophrenia or delusional thinking.
Wochok, who met with du Pont hours before the murder, remains haunted by his belief that he knew the man better than most but didn't see what was coming.
"It was very difficult to cope with," he said. "My constant thinking over many years has been: What could I, or anyone, have done to change what happened?"
Wochok knows now that du Pont hid his deteriorating mental state from him.
"There came a point where he only wanted to meet with me in the mornings, because that was when he was freshest," he said. "He wanted to control what I knew about what was happening."
Wochok has seen only the trailer for Foxcatcher but said he was looking forward to seeing the filmmakers' perspective on the events he lived through.
After the trial, Nancy Schultz settled a wrongful-death suit against du Pont for what sources said was about $35 million. The settlement went into a trust for her children.
She and her children moved to California, where her husband grew up and where members of the Schultz family still live. She started a foundation and wrestling club in her husband's name, and provided support and opportunities to former members of du Pont's Team Foxcatcher. She ended those programs in 2005, she said, to focus on her children.
Mark Schultz continued in athletic competitions, even winning an Ultimate Fighting Championship months after his brother's murder. He later returned to the West Coast and settled in Oregon, and has worked as a professional speaker. His autobiography, also titled Foxcatcher, will be published in November.
Work on the film Foxcatcher began in 2012. It was shot mostly in the Pittsburgh area, and the filmmakers used real wrestlers as consultants and drew from competition footage for action scenes. Nancy and Mark Schultz also worked closely with the actors.
Nancy Schultz remains close with her brother-in-law and other members of her late husband's wrestling community, she said. Her documentary project required her to return several times to the East Coast for interviews and to shoot footage, including a trip this year to what was once Foxcatcher.
As she saw the new plantings and buildings, she felt a sense of peace. After du Pont was arrested, he ordered the buildings painted black, including the house where the Schultz family once lived. The image lingered for years in her memory.
"It feels good to me, to see it gone," she said. "It's all new, like a fresh start."