Fingerprinting ASISTM Project Forensic Investigations.

Fingerprinting

ASISTM ProjectForensic Investigations

What are fingerprints?

On the fingers and palms of the hands and the toes and soles of the feet the skin is covered with friction ridges.

Photograph Paul Ricketts, 2006

Why do we have friction ridges?

Friction ridges are used to increase grip and the sense of touch.

Photograph Paul Ricketts, 2006

Friction ridges on the feet

Photograph Paul Ricketts, 2006

Friction Ridge Patterns

There are 3 main friction ridge patterns:• Loops - most common• Whorls• Arches - least common

Loop

Image courtesy J. Dook, 2006

Whorl

Image courtesy R. Henderson, 2006

Arch

Image courtesy J. Dook, 2006

Minutiae - fine detail

Image courtesy R. Henderson, 2006

Minutiae Patterns

Delta

Ridge ending

Bifurcation

Dot or island

Hook

Lake

Bridge

Image courtesy J. Dook, 2006

Example

Image courtesy J. Dook, 2006

Sweat Pores

It is possible to see small white “dots” on the friction ridges - the white dots are sweat pores.

Sweat pores

Image courtesy C. Henderson, 2006

Identical Fingerprints?

No two fingers have ever been found to possess completely identical friction ridge patterns.

Twins

RH: Left middle finger CH: Left middle finger

The boys both have a LOOP pattern but one of the twins appears to have cut his finger at some stage.

Image courtesy R. Henderson & C. Henderson, 2006

Twins Fingerprints

The minutiae or fine details of identical twin’s fingerprints are different.

Twins - minutiae

RH: Left middle finger CH: Left middle finger

Image courtesy R. Henderson & C. Henderson, 2006

How to take a fingerprint

An easy way is to use a pencil:

1) Rub an area on a piece of paper with a pencil.  2) Then rub your finger over the graphite on the paper.  3) Next, apply a small piece of sticky tape to the finger, lift and place

the tape on the sheet of paper.4) Make sure you clearly indicate from which finger the sample is

from.

An easy way to take a fingerprint

Photograph Paul Ricketts, 2006

An easy way to take a fingerprint -2

Photograph Paul Ricketts, 2006

An easy way to take a fingerprint -3

Photograph Paul Ricketts, 2006

Brushing for a fingerprint at a crime scene

Image courtesy J.Dook, 2006

Finding Fingerprints

Some fingerprints are obvious - these are called visible prints.

Photograph Paul Ricketts, 2006

Visible fingerprints on a door

Finding Fingerprints

Some fingerprints are NOT obvious - these are called latent prints.

How do you find latent prints?

Certain chemicals attach to substances that have been excreted by the sweat pores.

Using superglue

Using iodine

Using ninhydrin

References

Images• Fingerprints of J. Dook, R. Henderson and C. Henderson were

taken using a pencil as described on Slide 17. The prints were then scanned into Adobe Photoshop at a resolution of 1200dpi.

• J. Dook is the hand and foot model.• Slide 18 image taken of Police Constable Darren Fisher by J. Dook

at the Joondalup Police Academy, November 2005.• All other photography by Paul Ricketts, DUIT Multimedia, the

University of Western Australia.• Graphic design of slides by Trevor Hutchison, DUIT Multimedia,

the University of Western Australia.