Crime Scene Investigations, along with Criminal Investigations and Special Investigations make up the Lake County Sheriff's Office Investigations Bureau. Crime Scene Investigations is a specialized unit that is responsible for providing logistical assistance for the investigation of criminal activity.

The services provided by this unit are categorized in the following areas: Property and Evidence Section, Forensic Laboratory, Photographic, Laboratory, Fingerprint Section, and the Crime Scene Response Section. These services are provided to all the Bureaus within the Sheriff's Office, the fourteen municipalities in Lake County, and State and Federal Agencies. Presently, Crime Scene Investigations is staffed with twenty-one positions. These positions consist of a Lieutenant, a Sergeant, two civilian supervisors, eighteen full-time civilian employees.

The Property and Evidence Section is responsible for the intake, storage, and disposition of all property and/or evidence categorized as general evidence, controlled substance, money, jewelry, and weapons. Evidence received is properly documented, charted, and tracked throughout the system utilizing computer generated barcode labels. The evidence is preserved and maintained, whereby it can be located and presented at any given moment. Presently the Property and Evidence Section houses approximately 75,000 pieces of evidence. One Evidence Supervisor and five Evidence Clerks maintain this section.

The Forensic Laboratory has the most updated and sophisticated equipment for processing evidence in Lake County, with the primary focus on latent search and development. A variety of chemicals and powders are used in conjunction with the Lumalite, Crime Scope MCS-400, FSIS (Full Spectrum Imaging System) to develop and document latents on both porous and non-porous surfaces. Other equipment used in the laboratory are items such as a multi-chambered Superglue cabinet, Superglue vacuum chamber, DFO oven, Ninhydrin booth, and a Vacuum Metal Deposition Chamber. The laboratory is often called upon to search for and document Trace Evidence (hairs, fibers, body fluids, glass, etc.) as well as Bloodstain Pattern Analysis and Bullet Path Trajectory to aid in the reconstruction of crime scenes. "In Service Training" provides the Crime Scene Investigators the opportunity to refresh current skills and/or develop new techniques to be used in the laboratory or field. Eight civilian Crime Scene Investigators maintain this section.

The Fingerprint Section provides the services of classifying fingerprint cards of all incarcerated persons at the Lake County Detention Center. This section also provides latent evaluations and comparisons of unknown latent fingerprints against known individual prints. The Fingerprint Section is aided in this task with the use of the Automated Fingerprint Identification System (AFIS). A latent found on the crime scene is placed into the computer and a statewide database is searched for possible matches. These possible matches have to be compared by the Latent Analyst before an identification can be made. Another service provided by this section is the fingerprinting of employee applications of the Lake County Sheriff's Office and other county agencies. Three court certified civilian Latent Analyst, one full-time and one part-time Civilian Clerk.

The Crime Scene Response section provides a 24-hour, 7 day a week, on-call Crime Scene Investigator. Each Investigator is fully equipped to document the crime scene with digital video recordings, digital photography, measurements, computer generated diagrams and written reports. Each Investigator is professionally trained to recognize, identify, preserve, and collect all types of physical evidence. The Investigators each maintain a take-home Crime Scene Unit and are capable of immediate response to any type of crime scene, such as, but not limited to: Homicides, Suicides, Armed Robberies, Carjackings, Kidnappings, Sexual Batteries, Stolen Vehicles, and Burglaries. Other duties include building computerized composite (facial) drawings, plotting poster size crime scene diagrams, maintaining the Forensic Laboratory, and assisting in the Fingerprint section. This section consists of one Sworn supervisor and eight Crime Scene Investigators.