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Latent Investigations

A SPD latent print examiner dusts the inside of a vehicle for evidence.

The Seattle Police Department’s Forensic Support Services includes Latent Prints, the AFIS Identification Unit, Evidence Unit, Photo Lab and Video Unit. These units work out of state-of-the-art labs, and partner directly with the SPD CSI unit, the Regional AFIS system and the Washington State Patrol Crime Lab. Close working relationships and sharing information between agencies and systems is the key in the handling and processing of evidence.


The Latent Print Unit supports the Investigative and Patrol Operations with all aspects of forensic friction ridge visualization, preservation, and individualization.  The Latent Print Examiners analyze latent, or hidden, prints recovered from crime scenes, vehicles, and items of evidence submitted to the Latent Print Laboratory for processing.  The Examiners process items of evidence by using a variety of methods, including powders, fluorescent powders and dyes, chemicals, and optical techniques.  Those latent print impressions requiring photographic documentation are referred to the Photo Lab. 

Latent Examiners respond to, and process, major crime scenes for friction ridge evidence, often at the request of the CSI Unit.  An effective working relationship exists between the Latent Print Examiners and the CSI Detectives.  Efforts are coordinated in processing crime scenes containing bio-hazard materials.  Examiners also recover fingerprints, palm prints, and footprints from deceased and/or decomposed bodies, victims of crimes, and potentially violent suspects.

After latent print evidence is recovered, the prints are analyzed to evaluate the quality of the impression.  Those suitable latent prints are entered into the Automated Fingerprint Identification System (AFIS) by digitally enhancing the impression, scanning the impression, determining the minutiae, identifying the position of the impression, and inputting the impression.  A list is produced by AFIS that indicates possible candidates.  The Examiner compares each candidate impression with the latent print and determines identity or non-identity.  All latent impressions are evaluated and compared with any listed or AFIS-generated suspect.  All identifications made are verified by another Latent Print Examiner to ensure reliability. 

The Examiners often testify in criminal legal procedures concerning methods of analysis and results.  These procedures require the Examiners to keep current on legal proceedings regarding latent prints.  Constant study and review is necessary to gain control of this information and to testify with confidence.

AFIS Identification Section

AFIS LogoIdentification Technicians and Identification Data Specialists work with fingerprint images and arrest reports that are provided by King County Adult and Juvenile Correction facilities via livescan fingerprint capture workstations.

Once the fingerprint image is received and processed, the Identification Technician will perform comparison work to determine identification and associated criminal history of individuals. They will also classify and enter newly registered fingerprint images into the Regional Automated Fingerprint Identification System (AFIS). This information is available to all law enforcement agencies throughout the West Coast and Northwest Region.

The Identification Unit will work closely with the King County Department of Adult and Juvenile Corrections to assist in the identification of individuals prior to release from a King County Correctional Facility.  After the individuals have been identified and the charge information is researched and verified by the Identification Data Specialists, they electronically transmit the information to Washington State Patrol, thus ensuring that current, accurate arrest information becomes part of the individual’s rap sheet and is readily available to law enforcement personnel. The status of all transactions is closely monitored in the Livescan controller by the Identification Data specialists, and any problems are further researched and resolved. ID Data Specialists are responsible for informing Washington State Patrol when new or updated information becomes available that needs to be included in an individual’s rap sheet. Washington State Patrol records the received information and sends it to the FBI. When requested, ID Data Specialists also work directly with other law enforcement agencies to provide booking photos.

Find our more about the AFIS program by visiting


The SPD Video Unit is responsible for providing technical and forensic video support to patrol officers and investigative units. The Video Unit consists of four Video Specialists and a Manager.  This team supports programs such as Video Cameras in Patrol Cars, forensic retrieval and processing of evidentiary digital images, and documentation of crime scenes and other events.

The SPD Photo Unit is made up of four photographers. They specialize in crime scene documentation, scientific forensic photography, and also work closely with the latent print examiners to provide valuable photographic images for investigators and for use in court.

All of the team members of the video unit and photo lab have comprehensive training in forensic imaging and evidence retrieval. Additionally, they all have extensive experience and backgrounds in creative imaging and video production.

Because of this, both units also serve the valuable function to the department as pro-level production shops. The video unit creates educational, outreach and training videos for internal and public distribution and the photo lab takes a wide variety of high-quality still images at events, press conferences, and document the day-to-day work of SPD. Examples of the creative work of these units can be seen throughout our website.


The Washington State Patrol operates crime labs throughout Washington State. The biggest and the busiest lab is located in Seattle, and it works closely with the forensic support and CSI units and other investigative units of the Seattle Police Department.


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Seattle, WA 98124-4986
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