The polygraph seems to be the final nail in the FBI’s attempt at finding evidence against Jewell.
After the interrogation, sometime later, Shaw and other FBI members hand Jewell and Bryant a letter that states they will no longer be investigating him as a suspect.
Eventually, Jewell becomes fed up with all the questioning and says they don’t have any evidence to charge him.
Richard Jewell ended with a quiet showdown between Jewell (played by Paul Walter Hauser) and Watson Bryant (Sam Rockwell), and the FBI agents in charge of his case, led by Tom Shaw (Jon Hamm).