The Williamsport Bureau of Police Criminal Investigation Division is tasked with the investigation of major crimes, including homicides, aggravated assaults involving shootings and stabbings, rapes, robberies, crimes against children, burglaries, major thefts, and various other felony-level offenses.  The CIU also investigates some misdemeanor cases with special circumstances.

The Criminal Investigations Unit currently consists of (6) Agents who have received training in the latest methods of crime scene and criminal investigations. Members of this unit are also tasked with Internal Investigations and with conducting background investigations on all police applicants.