In the 1994 movie The Quiz Show congressional lawyer Goodwin investigates a popular quiz show for possible rigging.
He finds a concrete evidence by watching one of the contestants' show (James Snodgrass) where he answered the last question correctly; but the show host responded with "I'm sorry.". Then a doubletake occurs and the host says "Yes, that's correct!".
This leads Goodwin to find Snodgrass' house. In the house when Goodwin introduces himself and his intention, Snodgrass provides him with an envelope he had mailed to himself two days before the show containing the questions and answers that he was going to answer.
When Goodwin showed the envelope to Dan Enright, one of the producers of the show, he got so stunned and afraid that he tried to bribe Goodwin. But Goodwin refused.
Even Dan Enright got afraid; and it shows how concrete the evidences were. But in the rest of the show Goodwin doesn't use this evidence in court. He doesn't bring SnodGrass to court in order to testify against the show and its staff. He doesn't show the footage of Snodgrass' doubletook show presence to the court. He doesn't provide the envelope to the court. He only brings Herbert Stempel (another one of the contestants) who also suffers from a mental illness to testify in the court with no avail.
And at the end, Charles Van Buren testifies against himself; and Dan Elright and other staff falsely testify they didn't know anything about the rigging.
Why didn't Goodwin provide the court with Snodgrass' evidence while it proved to be concrete and intimidating to the show staff? Even while Van Buren told Goodwin that it doesn't prove anything he could just try.