Fingerprinting

History of Fingerprinting


Ancient civilizations would mark criminals through branding or maiming and the thief would lose the hand which was used to commit the given crime. In 1686 a professor noticed the ridges, spirals, and loops in the fingerprints but in doing so failed to mention this could be used for individual identification. The English finally began using fingerprints in 1858.


Types of Fingerprinting

Latent fingerprints aren't very apparent. They form from sweat from sebaceous glands on the body.

Plastic fingerprints are indentations left in soft, pliable surfaces like clay, wax, or paint, and are very visible.

Direct fingerprints are visible to the naked eye because they are left when fingers have blood, dirt, ink or grease on them and came in contact with a smooth surface.


Techniques/Chemicals

Taulk (Baby Powder) is used to lift fingerprints off of black surfaces.

Carbon is used to lift fingerprints off of glass surfaces.






Basic Shapes/Patterns of Fingerprints



Arches (Plain Arch & Tented Arch)- Found in 5% of fingerprint patterns





Loops (Radial Loop & Ulnar Loop)- Found in 60-70% of fingerprint patterns






Whorls (Plain Whorl, Central Pocket Whorl, Double Loop Whorl, & Accidental Whorl)- Found in 25-35% of fingerprint patterns



Procedure for Collecting/Lifting Prints

Once fingerprints are developed, several techniques can be used. Hinge lifters come in different color backgrounds to allow fingerprints to develop with different color powders, Rubber lifter is used when the adhesive side of the tape is applied to the powdered print, and cellophane tape is used on all surfaces, not just flat ones. It attaches to the contours of an object.

Handwriting

History of Handwriting



A person's handwriting has been recognized as a form of human identification for quite some time. This is the reason people are required to sign checks, deeds, and contracts. A person's signature lends authority and credibility to the document. A Forensic Document Examiner is the person who examines a document to gather facts that will establish the true nature of its origin and history.



Why do forensic investigators have trouble using handwriting analysis technique?


I think the reason forensic investigators have trouble using handwriting analysis technique is because handwriting unlike fingerprinting does not have a personal identification because many people could have the same handwriting where as no two fingerprints could be alike.


What do forensic scientists look for when analyzing handwriting?



Forensic scientists usually look for twelve basic characteristers when analyzing handwriting.



These 12 are:

• Line quality

• Spacing of words and letters

• Ratio of height, width, and size of letters

• Lifting pen

• Connecting strokes

• Strokes to begin and end

• Unusual letter formation

• Pen pressure

• Slant

• Baseline habits

• Fancy writing habits

• Placement of Diacritics

In class Handwriting Assignment







For our first handwriting assignment we had a note to record on a sheet of paper. Then we would pass that note on to our classmate and they would have to free hand it, trying their best to copy our exact handwriting. We would then pass the note on to another classmate and they had to trace over our note trying their best to directly copy our handwriting.



For our second handwriting assignment we had to write a check. We wrote the check in someone elses name (Joseph John Doe). After we wrote and signed the check in his name we cut the check up into little pieces and placed it in an envelope. The envelopes were then distributed around the room, and we had to put back together whoevers check we received and try and determine who the person is that forged the check by analyzing their handwriting.

Hair & Fiber

History of Hair and Fiber

Hairs, which are composed primarily of the protein keratin, can be defined as slender outgrowths of the skin of mammals. Each species of animal possesses hair with characteristic length, color, shape, root appearance, and internal microscopic features that distinguish one animal from another.

Techniques to ID Hair/Fiber

When we observed hair and fiber we put the hair and fiber on a glass plate and put it under a microscope and observed different types of human and animal hair.

Pictures and Analysis


During this lab we were given different hair samples such as asian hair, african american hair, dog hair, cat hair, etc. and we analyzed what each sample looked like under the microscope.






During this lab we were given different fiber samples to observe under the microscope. After looking at them under the microscope we would then make a prediction as to what we thought it looked like.

Blood Typing

Major types of Blood

Blood Type A: has A antigens on the surface of the red blood cells and B antibodies in the blood plasma.

Blood Type B: has B antigens on the surface of the red blood cells and A antibodies in the blood plasma.

Blood Type AB: has both A and B antigens on the surface of the red blood cells and no A or B antibodies at all in the blood plasma.

Blood Type O: has neither A or B antigens on the surface of the red blood cells but has both A and B antibodies in the blood plasma.



Ability of Blood mixing and Transfusions

Blood transfusion is the process of transferring blood or a blood component from one person, the donor, to another person, the recipient. Blood transfusions are given to increase the bodies ability to carry oxygen.

Blood Group	Antigens	Antibodies	Can give blood to	Can receive blood from
AB	A and B	None	AB	AB, A, B, 0
A	A	B	A and AB	A and 0
B	B	A	B and AB	B and 0
0	None	A and B	AB, A, B, 0	0

Blood Type O is referred to the "Universal Donor" because all blood types can receive O.

Blood Type AB is referred to the "Universal Receiver" because it can receive all blood types.

Positive and Negative Blood Types?

When we are told our blood types we are given a letter consistings of A, B, or O followed by a (+) or a (-) sign. This is called the Rh System.

Generic Makeup Blood Type

++ Positive

+- Positive

-- Negative

Lab Findings






During this Lab we tested different Blood Types reactions with Anti-A Serum and Anti-B Serum.

Blood Type A

Reaction with...

Anti-A Serum: Formed a precipitate.
Anti-B Serum: Remained clear.. not colorless.

Blood Type B

Reaction with...

Anti-A Serum: Remained clear
Anti-B Serum: Formed a precipitate

Blood Type AB

Reaction with...

Anti-A Serum: Formed a precipitate
Anti-B Serum: Formed a precipitate

Blood Type O

Reaction with...

Anti-A Serum: Remained Clear
Anti-B Serum: Remained Clear

From this we can gather that Blood Types A & B both have a clear and a precipitate one being opposite of the other and Blood Types AB & O have two of the same.