Resurrecting the Champ is a 2007 movie about a journalist who thinks that a story about a now-homeless boxer could be his big break. The two become friends as the journalist, Erik, interviews and researches the Champ, but it's revealed in the end that the Champ had been lying to him and was in reality a different boxer who the Champ had once beaten.
While Erik does research and interview the Champ, he ends up not finding out that he's made an error until the story has already run. He even has a moment where he is told that the Champ is not who he says he is, but he ignores the warning in favour of his article. This results in him casting the Champ in a false light, as he doesn't have all the information and creates a false image that the Champ's son disagrees with.