Fingerprints

Fingerprinting has always been used, but it wasn’t until modern times that it was used for identification. In ancient Persia fingerprints were used to sign documents and were continued to be used as a way for singing contracts for many years. It wasn’t until 1880 that the importance of fingerprints for identification was realized by Dr. Henry Faulds. Even with Faulds research the Bertillon method of identification more popular. The Bertillon method of identification was involved by Alphonse Bertillon and involved taking the measurements of a person to identify them. Finger prints were used as a secondary means of identification until a man was wrongly jailed because he shared similar measurements with his twin brother. From that point on fingerprints were used as a primary means of identification. In 1892 Joan Vucetich was the first to use fingerprints in a criminal investigation identifying a murderer. Through out the years finger printing became more common being adopted by US prisons, the Army, the Navy and the Marines. As finger printing spread hundreds of millions fingerprint cards were made around the world. To keep track of criminals and citizens alike automated systems, such as AFIS (1946), were created around the world. The FBI posseses the largest AFIS system and all states will posses their own AFIS systems. Today fingerprinting is an invaluable in the fight against criminals world wide.

There three types of fingerprints, direct, latent and plastic. A direct fingerprint is visible because it is usually left in one of these mediums: grease, dirt, blood, ink, or paint and does not require dusting before lifting the print.

A latent print is not visible to the naked eye and is usually left on either dark or glass surfaces. To lift a latent print on glass a darker powder, such as black carbon, is required when dusting to see the contrast before lifting. On a dark surface a lighter dusting powder, such as aluminum powder, is required to see the contrast before lifting.

Finally plastic prints are ridge impressions and impressed into a soft medium such as wax, putty, soap, or dust.

Besides darker and lighter powders like black carbon powder and aluminum powder there are other techniques and chemicals to lift prints, such as magnetic-sensitive powders, fluorescent powders, and the iodine fuming process. The different types of prints and different locations of the prints require different chemicals and techniques. For latent prints iodine fuming and fluorescent powders are most effective. Powders should be used when the surface is a dark hard surface lighter powders should be used and for glass surfaces darker powders should be used. For softer surfaces chemicals should be used.

(These are the eight types of finger prints).


Sources:
http://www.bxscience.edu/publications/forensics/articles/fingerprinting/f-fing03.htm http://odec.ca/projects/2004/fren4j0/public_html/types_prints.htm http://www.onin.com/fp/fphistory.html

Hand Writing

At its base hand writing analysis for forensic purposes is simple: by comparing samples of the same hand writing it can be determined if it is authentic or a forgery. This possible because to a trained professional hand writing is like finger prints; unique to the individual.

(Free hand copy of
my hand writing)
Graphology can be considered the forerunner of forensic hand writing analysis. The two use similar components as a means of analysis. Although the two are similar hand writing analysis is based in science while graphology is based in psychology. Graphology started from the idea that hand writing originates in the brain and therefore can be used to create a psychological profile of the writer, while hand writing analysis is used for two main purposes. “One is to authenticate documents and other is used to link a suspect to a crime”1. Hand writing analysis seem basic but is actually very difficult because unlike finger prints writing can’t be broken down into eight specific classifications, it is built on comparative analysis on the premise of twelve characteristics. They are line quality, spacing of words, size of letters, lifts of the pen, connection of strokes, beginning and ending of strokes, unusual latter formation, pen pressure, slant, baseline habits, fancy writing habits, and placement of diacritics. By using these characteristics forensic hand writing analysts are able to notice subtle differences in hand writing which allows them to authentic documents and exclude or include suspects in a criminal criminal investigation.

(Traced copy of my
hand writing)

(Free hand and traced copy of my handwritng in a ransom note)

Sources:
(1) http://www.enotes.com/forensic-science/handwriting-analysis
http://forensicscience.suite101.com/article.cfm/forensic_or_scientific_handwriting_analysis

Hair and Fiber

Hair and fibers are usually the most abundant evidence at a crime scene, but often go unnoticed. When there aren’t any prints, hair and fiber are a crime scene investigators greatest ally.

Fibers are very transferable and are now commonly used to link a suspect to a crime. They can be classified into two categories, natural and man-made. Natural fibers are things like wool and cotton, while man-made fibers are things like polyester and nylon. By taking cross sections of fibers and putting it under a microscope are able to determine what the fiber is, who manufactured it and where it came from.

Hair is also common at a crime scene and by looking at a hair under a microscope a forensics specialist can see evidence of drug use, they can tell what animal the hair is from, they can determine the ethnicity of the person among many other things. They do this by identifying and classifying the shaft, medulla and cuticle of the hair.

Hair and fiber may seem insignificant, but in fact are some of the most important evidence at a crime scene.

Sources:
http://stereoscope.com/?p=3
http://www.fbi.gov/hq/lab/fsc/backissu/july2000/deedric3.htm

Hair and Fiber Pictures

Color Treated Hair

Thin, possible blonde shaft.

Difficult to see.

African American

Brown shaft, black medulla.

Asian Hair

Cut end, brown shaft, black medulla.

White Male Hair

Purple shaft. Wide, gold medulla.

Cat Hair

Stacked appearance, frayed cuticle, dark shaft.

Classified as coronal.

Dog Hair

Clear shaft with dark medulla.

Also was the unknown hair.

Synthetic Hair

Thready appearence, brown shaft.

Source:

Pictures from Olivia's blog

http://www.okretschmerforensics.blogspot.com/

Blood Type

There are four major types of blood groups: A, B, AB, and O. Although there are only four major blood types there are subclasses which come into effect during blood transfusions. Blood transfusion is the transfer of blood from one person to another and occurs after major blood loss. The reason behind it is your body can’t produce enough blood fast enough and therefore your body can’t oxygenate it’s self, so blood is transferred intravenously through an IV drip to replace the lost blood and oxygenate your body. The major blood types can each be broken down into two subclasses based on the absence or presence of protein, making it either positive (+) or negative (-). This is called the Rhesus factor; if protein is present in the blood it is Rh positive and if protein is absent than it is Rh negative. For a successful transfusion to occur the same blood type with the correct Rh factor is needed or else a hemolytic transfusion will occur, which results in your immune system attacking the transfused blood cells and your blood will agglutinate (clump together). This is why usually O blood is transferred because it doesn’t have any antigens causing it to be accepted by the immune system regardless of blood type, which is why it is called the universal donor.

In the blood type lab we tested the blood types for A and B antigens by taking two samples of each blood type and adding A antigen to one sample and B antigen to the other. After mixing the sample with the antigen if the blood was grainy then it was positive for that antigen and if it was gelatinous it was negative for that antigen. This chart represents our findings.

Sources:
http://www.fi.edu/learn/heart/blood/rh.html
http://nobelprize.org/educational_games/medicine/landsteiner/readmore.html
http://health.yahoo.com/blood-treatment/blood-transfusion/healthwise--tc4111.html
http://www.nhlbi.nih.gov/health/dci/Diseases/bt/bt_whatis.html Picture: http://healthcareblog.experience.com/2008_04_01_archive.html http://schools-wikipedia.org/wp/a/ABO_blood_group_system.htm

Final Investigation

Purpose: To investigate and solve a crime using forensic analysis techniques learned in class.
Crime: Robbery.

Investigation:
When we arrived at the scene there were six pieces of evidence (a wallet, a beaker with a fingerprint, a ransom note, blood, and two types of hair) and eight possible suspects. We identified the wallet found at the scene as Mike Kelly's suggesting he was either robbed or was involved in the crime. There was a beaker next to the wallet with a ulnar loop like Mike Kelly's fingerprints. We checked his records and found he's an educator. Also there was a ransom note in an envelope that read "I have your diamond ring". The hand writing matched Ralph Nelson's hand writing. With this new information we could rule out Mike as a suspect. Next we found blood near the beaker, suggesting a struggle. The blood type was A which matched Jenny Cho's, a chemical engineer, and Ralph Nelson's, a college professor. Also present was Asian or African American and Caucasian hair, placing Jenny Cho and confirming Ralph Nelson's and Mike Kelly's presence at the scene. Upon looking at Jenny Cho's records we found she had a prior arrest for petty theft in '88.

Summation:

Taking into account all the evidence, here's what happened Jenny Cho had been having an affair with Mike Kelly behind Ralph Nelson's back. When Mike proposed to Jenny she decided to leave Ralph. Ralph became angered and wrote Mike a note to lure him out. When they met they fought and during the struggle some of Mike's hair fell out and either Jenny's hair transferred from Ralph or some of Ralph's hair fell out. Also during the struggle Mike dropped the note and his wallet fell out his jacket. Mike then took out a beaker and hit Ralph causing him to bleed. Seeing Ralph unconscious Mike ran away and Jenny Cho came upon Ralph and helped get away, but not before she took the money from Mike wallet.

Pictures: http://www.okretschmerforensics.blogspot.com/