Lance Armstrong documentary changed radically as allegations spread.

When documentary filmmaker Alex Gibney (Enron: The Smartest Guys in the Room, Taxi to the Dark Side) was offered unprecedented access to seven-time Tour de France winner Lance Armstrong for his 2009 comeback ride, he was unaware of what his story would become.

But as allegations continued to spread in the years that followed about Armstrong’s possible PED use - which he officially admitted to in an interview with Oprah Winfrey this past January - Gibney came to the realization that his film was no longer about the world’s most inspiring athlete, but its greatest deceiver.

“The film we had made - and was virtually completed - was no longer relevant,” Gibney revealed during a press conference Monday morning at the Toronto International Film Festival.

“I felt like I had been used, to some extent, as part of a con.”

In The Armstrong Lie, Gibney delves into the maillot jaune’s biggest cheat to uncover the truth about the career-long doper and cheating for which he would become known.

Told through the eyes of Armstrong himself, as well as the teammates and competitors he destroyed along his path to glory, the film perfectly captures the disappointment suffered by millions of cancer survivors and cycling fans worldwide who were deceived by the athlete—including Gibney himself, who frames a chunk of the film around the relationship built between Armstrong and the director in the years leading up to his acquittal from international competition.

“By putting myself in the film, I had to reckon with the whole position of the fan’s need for a dream…for a kind of perfect story,” he said. “And Lance’s story was the most perfect story of all.”

But as Gibney progressed in his work, he quickly discovered the story he had begun to tell wasn’t simply about a fraudulent hero, but the ways in which celebrities use their power for whatever means necessary.

“It’s about something much more intangible - about what we look for in the whole sporting endeavor,” Gibney said.

“When you see in retrospect that somebody abuses their power to go after people who are trying to tell the truth…I think they’re deeply offended by it.”