Hill joined the Wayne County Sheriff's Department in 1957, but quickly became disillusioned with the slow pace. In 1959 he moved to the Detroit Police Department. In 1969 he was promoted to detective and was assigned to the homicide division the following year. Over the next decade, Hill rose to national attention for his ability to obtain confessions out of the most notorious killers. He was involved in the investigation surrounding the Atlanta Child Murders in 1979 that ultimately resulted in the trial and conviction of Wayne Williams.