During the filming of the episode "Walkout", Carroll O'Connor began to experience fatigue. After being checked by the set doctor, it was discovered that he needed sextuple heart bypass surgery, due to years of heavy smoking. During the last four episodes of the season, Joe Don Baker was brought in as Tom Dugan, a replacement for Chief Gillespie, who was said to be away at a police training conference at Quantico. The episodes where Gillespie was away were "Fifteen Forever", "Ladybug, Ladybug", "The Pig Woman of Sparta" and "Missing". Dugan was appointed acting chief by Councilwoman White, but he was actually working undercover for the FBI in an attempt to stop the assassination of a civil rights preacher during a visit to the town by a white supremacist group (that is not revealed until the Season 3 episode "Anniversary"). The season finale "Missing" has the chief being kidnapped upon his return to Sparta by two men in pig masks, and the police and the FBI are at wit's end trying to locate him and those who are responsible. O'Connor wanted the chief to undergo heart surgery in the storyline, but the husband and wife producers came up with this storyline instead. It was the final straw in a long line of complaints; these producers were fired at the end of the season, with O'Connor becoming the executive producer for season three and beyond.