Developing Latent Prints at Crime Scenes

The Laboratory is the best place to develop latent prints; however, it is sometimes necessary to develop latent prints at crime scenes.

• Caution should be taken to prevent destroying latent prints.
• Examine all evidence for visible latent prints before using any latent print development processes.
• Photograph visible latent prints first.

Fluorescence examination
with a filter.

• Examine evidence with a laser or an alternate light source to find latent prints.
• When using latent print development processes, refer to the manufacturer's instructions and the safety data sheets. Use protective equipment.

• Caution should be taken when using cyanoacrylate processes. Cyanoacrylate glue fumes should not be applied to wet surfaces.
• Use print powders to develop prints. Use black and gray powders because other colors are difficult to photograph. Use black powders on evidence with a light background. Use gray powders on dark or reflective evidence. Do not apply powders to greasy, bloody, dusty, or putty-covered evidence. Allow wet evidence to dry before applying powders.

Preparing specimens for
cyanoacrylate processing.

Photographing and Lifting Latent Prints

• Photograph latent prints separately.
• Photograph latent prints developed with fingerprint powders before lifting.
• Use transparent, black, or white rubber lifting tape to lift latent prints. When transparent tape is used, the color of the backing card should contrast with the color of the powders.
• Use a medium-format camera with adaptability to one-to-one photography.

Accelerating a chemically
developed print.

Photograph of a latent-bearing surface.

• Photograph prints with a scale and an identification label that includes the reference number, date, collector's initials, and the location of prints. The scale and label should be placed on the same plane as the prints.
  
  
• Fill the frame completely.
  
  
• Photograph latent prints close to each other in one frame.
  
  
• Use T-Max 400J film. Set the f-stop to f/8. Adjust the shutter speed setting until the green light appears. Take exposures of each latent print by bracketing. Take three exposures.
  
  
  • Original exposure.
    
    
  • Underexposed image.
    
    
  • Overexposed image.
    
    
• Maintain a photographic log that includes the reference number, date, collector's initials, the location of prints, and other pertinent information.

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• Place nonporous evidence in separate protective coverings such as thick transparent envelopes or suspend in a container so that there is minimal surface contact. Place porous evidence in separate protective coverings such as paper envelopes. Stabilize the evidence to avoid movement or friction during shipment.

Fingerprint card.

• Submit the fingerprints and palm prints of all personnel who handled the evidence and of all individuals who are suspects in the investigation with the evidence. All fingerprint cards must include pertinent information.
  
  
• Palm prints should be taken on a separate card, not on the reverse side of a fingerprint card.
  
  
• When fingerprint cards or major case prints are submitted for comparisons with evidence, the criminal/suspect or noncriminal/elimination nature of the prints should be stated in the communication.
  
  
• When inked prints are submitted separately, a communication should be sent with the prints referencing previous communications and pertinent numbers.
  
  
• Fingerprints from decomposed bodies are often not classifiable, which precludes a search of the FBI's fingerprint files. An individual fingerprint may, however, be suitable for identification purposes. If less than ten legible fingerprints are obtained, submit the available fingerprints and a complete physical description of the unknown deceased.
  
  
• Legible, unknown deceased, ten-print fingerprint cards should be submitted for identification purposes to the FBI's Criminal Justice Information Services Division at the following address. Questions concerning ten-print fingerprint card submissions should be directed to 03-9702366.

• When printing the deceased, obtain inked fingerprints and palm prints for comparison with latent prints. If legible prints are not obtainable, amputate the hands or the fingers with authority from a coroner or a medical examiner and submit the evidence to the Laboratory.
  
  
• Pack each finger in a separate container, labeled RIGHT THUMB, RIGHT INDEX, and so on. Pack the hands or fingers in unbreakable, watertight, and airtight containers with a 70 percent solution of alcohol. All human remains will be returned to the contributor.