The Crime Scene Investigation Unit (CSIU) is a part of the Criminal Investigation Division of the Randall County Sheriff's Office. It is a multi-functional lab and crime scene investigations unit specializing in the preservation, processing and analysis of criminal evidence.

The following is a list of day-to-day functions of the CSIU:

- Process crime scenes

- Comparison and identification of fingerprints

- Crime scene and latent print photography

- Field testing of drugs

- Collection, preservation, storage and disposition of evidence

- Use of computerized fingerprint system

- Train and assist field identification officers