The Sheriff's Office Investigation Bureau is where most felony crimes and other intricate matters are investigated. When a patrol deputy takes a major incident report in the field, it is routed to the Investigation Bureau for follow-up. Depending on the type of incident, the report will be routed to one of the following units: Property Crimes Unit, Violent Crimes Unit, Domestic Violence/Sexual Assault Unit, Narcotics Unit, Crime Scene Investigations Unit, or the Coroner's Unit.

Detective sergeants, who report to the Investigation Bureau lieutenant, supervise the individual units. The Investigation Bureau has thirty-five detectives assigned to the various units, plus a number of clerical staff and other assistants.

Detectives are selected from the deputy ranks of the Sheriff's Office through a competitive process. Successful candidates must have a record of high performance in the patrol division and show an aptitude for detailed investigations, plus be skilled in interviewing/interrogations, report writing, and working as a member of a team. An assignment to the detective bureau reflects a high regard for a deputy's skills and abilities. Detective assignments may go well beyond the usual three-year-mark if the detective continues to prove that he or she is the most skilled and effective individual for that position.