The Bureau tasked with primary investigative responsibility for the Harford County Sheriff's Office is the Investigative Services Bureau (ISB). The Sheriff's Office ISB is under the command of a Major. The purpose of the Investigative Services Bureau is to investigate reports of criminal activity and to work with all local, state, and federal agencies to bring offenders to justice. To accomplish this mission, the work of the ISB is divided into two divisions:
The Criminal Investigations Division consists of the Major Case Unit, Burglary Unit, Megan’s Law Unit, Computer Forensics, Evidence Collection, Victims Services, and detectives assigned to the Harford County Child Advocacy Center (CAC) including the sergeant who manages the Center. The Special Investigations Division encompasses the Drug Task Force, Criminal Intelligence Unit, and the Homeland Defense Unit.