Dusting CJ

Latent Fingerprints

• A inked fingerprint is a direct impression of an individuals finger.

• Latent prints are invisible and require powder or some other method to lift the print.

• Latent prints are prints that are left on a surface by contact with the friction ridges. 

• Latent prints result from a mixture of secretions from sweat glands.

• These prints usually need to be seen with a laser beam or other high energy light source known as a Blue Max light.

Dusting Procedure 

1. The brush should be clean and free from oils or other materials.

2. The brush should be swirled vigorously to remove excess powder.

3. The brush should be dipped lightly into powder in a swirling motion, lifted swirled again, then applied lightly to surface in circular motion.

4. Once print is visible, dust lightly in direct of ridges until visible.

5. Do not over dust

6. Lift print with fingerprint tape. Apply tape from roll over print and rub smoothly to remove air bubbles. Pull up and away from roll and cut.

7. Apply to card

Patent Fingerprints

• Patent prints are all visible.

• There are three types of patent fingerprint impressions.

1. Patent prints are prints that are visible to the naked eye. Ex. blood, grease, etc. They are referred to as a positive transfer impression.

2. The second type of patent impressions results from the removal of surface material, creating a negative impression.

3. The third type of a patent impression results from contact with a soft substance such as clay, fresh paint, and where the ridges are impressed onto the surface. 

Surfaces

• Smooth non porous surfaces such as glass and glossy plastic need dusting powder to lift a print.

• Wet surfaces such as blood and grease need cyanoacrylate (superglue) fuming to lift the print.

• Rough non porous surfaces like pebble or grainy surfaces need cyanoacrylate.

• Plastic type foam like styrofoam cups need SPR (small particle regents). 

Examining for Prints

1. Visual examination: Search should start with methods that are non-destructive. A visual search will be done first and if no prints can be found you will need to use a laser or ultraviolet light source.

2. Photograph prior to lifting: Any print found should be first photographed.

3. Processing with physical or chemical methods: Choice for method depends on the surface the print was found on.

4. Photograph after development: Photograph after each step.

5. Sketch: Document the location on the lift card for future reference. 

Fingerprint Card 

• The card should be labeled Fingerprint Card and contain the following information:

1. Case number - starts with last two digits of the year ex. 25

2. Date/Time

3. Type of offense: Murder

4. Location/Address: 45 Reinhardt rd, Wayne NJ, 07470

5. Victim - Jane or John Doe

6. Location where print was found: F126 mirror

7. Print taken by: Me! (Officer Tuguz)

8. Type of print 

9. Sign back with ID number