Walter Mills is an Internal Affairs Division Officer with the Metro-Dade Police Department. In 1988, Mills was brought in to investigate the disappearance of gubernatorial candidate Tom Pierce, and focused his inquiry on Detectives James "Sonny" Crockett and Ricardo "Rico" Tubbs, who were to see Pierce before his vanishing act. Mills is especially contemptuous of Crockett, whose attitude rubs Mills the wrong way. Crockett and Tubbs were cleared when Pierce reappeared to resume his campaign. Later in 1988, Crockett went through a traumatic experience where amnesia caused Crockett to change to his drug dealing alter-ego Sonny Burnett, Mills testified at a hearing about Crockett's attitude and that he felt Crockett is capable of "faking it" to evade arrest and jail for his actions as Burnett.