1. Thank you Maharaj!

2. Latent Fingerprints!

3. What are latent fingerprints?
Latent fingerprints are invisible.
Fingerprints are formed from material on the fingers that is pressed upon a surface.

4. What causes latent prints?
Oils secreted by the fingers
Sweat on the pores on the skin
Proteins from the surface of the skin

5. Things that affect oil or sweat can leave bad prints
What kind of things do you think would affect oil?

6. Are all surfaces likely to have latent prints?
Hard and nonabsorbent surfaces
Easy: Glass, glossy tile, porcelain, lacquered furniture, smooth metal.
Involved: Paper, painted surfaces, drywall, cardboard, leather, most dashboards.
Difficult: Organic surfaces (tree leaves, fruit peels, feathers) or treated surfaces.

7. How can we see latent prints?
There are 6 basic methods.
We will cover 3 of them:
Print powders
Superglue fuming
Silver nitrate

8. Lifting latent prints with powders
Powders stick to the oils left behind on fingerprints
Different powders are used for different surfaces

9. Types of powders...
Gray powder, aluminum dust, is used on dark surfaces. It is also applied to mirrors and metal surfaces.

10. Black powder, basically charcoal, is applied to white or light colored surfaces.

11. Fluorescent powders are also used to develop latent fingerprints
Fluorescent powders are also used to develop latent fingerprints. These powders light up under UV light.

12. How to dust for fingerprints...

13. Super glue fuming method
Super glue is placed on tray with the evidence.
The fumes are then created by heating the glue.

14. Fumes from the glue stick to the latent print, usually producing a white colored latent print.

15. How to use the superglue fuming method...

16. Silver nitrate method
Silver nitrate works well on porous surfaces like paper or fabric.
Based on the reaction of silver nitrate with the salt and proteins in fingerprints.

17. It is very good on old fingerprints when the other methods usually fail.
Only use it after trying the other methods, as it will destroy the print.

18. How to use the silver nitrate method...