The Criminal Investigations Division is comprised of two units, the Criminal Investigations Unit and the Narcotics Unit.  The Criminal Investigations Unit is responsible for investigating felony crimes against persons and property, juvenile crimes, and School Resource Officer program.  This unit is assigned to a variety of cases ranging from homicides, sex offenses, burglaries and other felony cases.  The Narcotics Unit handles narcotics trafficking and dealing, as well as street crime related incidents.

• The Division works closely with the Patrol Unit in identifying criminal patterns and works to conduct proactive, preventative activities addressing neighborhood concerns.
• Detectives work in conjunction with multiple criminal justice agencies at both the state and federal level including the States Attorneys' Office, the United States Attorney's Office, the Bureau of Alcohol Tobacco and Firearms, the Federal Gang Task Force, the Quad City Metropolitan Enforcement Group, Drug Enforcement Agency Task Force, Rock Island County Probation and Patrol, and other police departments on a daily basis. 
• Conducts follow-up investigations on juvenile crimes.
• Focuses on early detection and counseling for juveniles to deter juveniles from a career in crime.
• Assists students in recognizing and resisting pressures to experiment with drugs and alcohol.
• Works with other agencies to more effectively deal with criminal activity by and against juveniles.
• Works with school administration and staff to develop and present curriculum on topics that improve the safety and welfare of students in our community.
• Refers juveniles to the Youth Service Bureau by utilizing Teen Court.
• Proactively investigates narcotics related and street crime activities.