Handwriting has a long history, dating back to the beginnings of civilization when the Sumerians wrote on wet clay tablets. Thoughout the years, handwriting has not only become a way of documenting events and transactions, but a symbol of a culture.
Handwriting can be used in forensics as a means of identifying people and forgeries, and has also been used in psychology, called Graphology. Graphology can be used to determine personalities or mental disorders, useful in many feilds.
Specialists can use handwriting analysis in forensics to identify forgeries and ransom notes. Becuase each style of handwriting is distinct, it is very hard to imitate another's handwriting as your own handwriting characteristics will often show through.
Thursday, August 27, 2009
Handwriting: A History
Handwriting: Innaccuracies in Analysis
Although handwriting analysis has been proven useful in forensic science, it has many shortcomings that can make its authority in investigations and court questionable. In the past, convincing forgeries have made people question the 'science' of handwriting analysis.
Amongst a very precise science like Forensics, handwriting analysis can appear more speculative than things like fingerprinting, hair and fiber analysis, and DNA analysis. Here are some reasons why handwriting analysis can be proved ineffective in an investigation:
-Handwriting, although hard to imitate, can be copied by a professional. There have been instances in the past where professionals have fooled analysts. Handwriting is not always the only thing forged--- paintings, currency, and government documents like passports have been forged in the past and can be used by criminals to cover their tracks.
-To correctly match handwriting to a person, you need a sample of that persons natural handwriting (called an exemplar). Exemplars can be hard to find, as it is difficult to match capitol letters, cursive, and print.
-Ransom notes can simply be printed from any computer in the world. Printers are now available on a huge (and occasionally public, like libraries and stores) scale.
-A persons handwriting will change with age and physical weakness.
Handwriting: Techniques Used to Identify Handwriting/Forgeries
A forensic scientist will look at the handwriting in question and compare it to the known sample. Here are some things to look for when you're comparing handwriting:
-Where are the i's dotted? Directly above the letter? Is it a dot or a circle? How about the t's?
-How big are the letters? How close are they together? How much space is between words?
-How hard does the writer press the pen/pencil to the paper?
-Is the writing in a straight line? Does the writer tend to gravitate up or down?
-Do the letters flow together or is each letter printed separetly?
-How do the capital letters connect to the lowercase ones?
-Do the individual letters slant one way or another?
-Are there any unusual characteristics about the writer's handwriting? A's, t's, k's, g's, and q's are a few examples of letters that can vary widely from person to person.
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Monday, August 24, 2009
Fingerprints: A History
Fingerprints were first used in ancient Babylon and China as a way for people to 'sign' clay tablets as business transactions. Later on, it was noted that no two fingerprints were alike as the English began using them to create binding contracts in 1856, starting with Sir William Hershel.
Throughout the next 50 years, many studies were published over the use of fingerprints in identifying people, including articles in the Scientific Journal by Dr. Henry Faulds and a book 'Fingerprints' by Sir Francis Galton in 1888.
By 1892, the first criminal identification using fingerprints was made in Argentina. In 1903, the New York State Prison began to systematically collect and file prints in a database. Between 1905 and 1908, The Us Army, Navy, and Marine Corps joined the bandwagon and began to use fingerprinting.
Later on, in 1999, the FBI stopped manually taking fingerprints on paper and instead used computerized AFIS (Automated Fingerprint Identification System) to catalog prints. There are currently hundreds of millions of fingerprints on file.
Fingerprinting remains an effective method of identifying people because, while physical features change, fingerprints do not. No two people have the same fingerprints, and fingerprints can be classified to narrow down the suspects.
Here is one of the comments I posted in response to an ongoing debate (check out the comments for more!) that gives my opinion on the question of whether or not the government should be able to record and file every US Citizen's fingerprints. A good portion of the ficticious case was speculation-- comments are appreciated!
------I agree that fingerprinting and things like retinal scans or DNA tests can be combined to provide more accurate results, but even if a fingerprint has been on a surface for days or weeks, it offers a solid database of suspects and a pool of people to question about the crime scene.
Say, for example, that a CEO is murdered in a hotel lobby. Prints lifted off the letter opener which was used as the murder weapon include those of the hotel manager, three desk receptionists, the janitor, and two unknowns. Becuase the hotel's staff was working in close proximity to the crime scene, they are automatically considered as suspects and questioned. The other two unknowns prove to be a salesman that had checked in last week and a disgruntled employee that had worked under the murdered CEO. The salesman, receptionist, and employees were questioned and they confirmed the murderer's arrival and depature at the hotel surrounding the date of the murder.
Although there were 6 innocent people, by questioning them and having everyone's fingerprints, the invesigators were able to make the connection between the murderer and victim. Forensics is about making connections-- between DNA samples, fingerprints, handwriting, hair, fibers, and much more.
Fingerprints: Types
Direct Fingerprints (also called Visible or Patent): Fingerprints that have come in contact with substance and then left an impression on a smooth surface that are visible to the naked eye.
Latent Prints: Fingerprints, formed from from sweat or oil on your fingers, that are left on a surface. They are not visible to the naked eye, but can me made so by dusting or chemicals.
Plastic Prints (also Impressed): Fingerprints left in a malleable or soft material, like clay, paint, or wax.
Fingerprints: Techniques to Develop Prints on Hard/Porus/Smooth/Nonabsorbent Surfaces & Procedures for Collecting/Lifting Prints
Hard, Smooth, and Nonabsorbent Surfaces(tiles, glass, lacquered/painted wood): Use Carbon or Charcoal powder for light-colored surfaces. Use grayish-white powder for dark surfaces). Fluorescent powder, visible under ultra-violet light, can also be used. The powder will stick to the sweat and oils left behind and leave a visible print that can be lifted.
Soft and Porous Substances (cardboard, paper, cloth): Chemicals are used, such as Iodine, Silver Nitrate, and Ninhydrin. Iodine is used in a fuming process to photograph the prints. Silver Nitrate can be used a last resort when other methods do not work as it renders the other tests ineffective. A 3% solution is dusted on the print and then an ultraviolet light will reveal the prints as reddish-brown. Ninhydrin is made into a .6% solution by dissolving it in ethyl alcohol or acetone and sprayed on the print, causing it to turn dark purple in an hour or two.
Fingerprints: Basic Patterns & Shapes
There are eight basic kinds of fingerprints listed in this picture. The loop is the most common, although most people have many different kinds of prints on different
fingers.
Here are some pictures I took of my own fingerprints:
My left hand.
Right hand, middle finger= Ulnar Loop
Right hand, pointer finger= Ulnar Loop
Left hand, middle finger= Tented Arch
Saturday, August 8, 2009
Bibliography (Includes Picture Sources as Well)
1. http://www.globalsecurity.org/security/systems/images/print-types.jpg (pic)
2. http://www.onin.com/fp/fphistory.html
3. http://www.reachoutmichigan.org/funexperiments/agesubject/lessons/prints.html
4. http://www.usmarshals.gov/usmsforkids/fingerprint_history.htm
5. http://www.handwritingforensics.com/
6. http://odec.ca/projects/2004/fren4j0/public_html/types_prints.htm
7. http://www.fbi.gov/hq/lab/fsc/backissu/july2000/deedric1.htm
8. http://www.keratin.com/aa/aa012.shtml
9. http://www.crimeandclues.com/hair_evidence.htm
10. http://www.castleviewuk.com/Frameless/Forensics/off-site_subjects/hair.htm
11. http://www.sd281.k12.id.us/thornton/papers/Forensics%20of%20Hair%20Analysis.ppt
12. http://en.wikipedia.org/wiki/Spectrometer
13. http://www.law.umkc.edu/faculty/projects/ftrials/SaccoV/s&vaccount.html
14. http://www.law.umkc.edu/faculty/projects/ftrials/frank/frankaccount.html
15. http://images.google.com/imgres?imgurl=http://schools-wikipedia.org/images/594/59443.png&imgrefurl=http://schools-wikipedia.org/wp/a/ABO_blood_group_system.htm&usg=__1IrZKjst0GAwOgR8tuOMI9t7usg=&h=279&w=400&sz=42&hl=en&start=1&um=1&tbnid=rod_iGx23r5ixM:&tbnh=86&tbnw=124&prev=/images%3Fq%3Dblood%2Btyping%26hl%3Den%26safe%3Dactive%26sa%3DN%26um%3D1 (Pic)
16. http://images.google.com/imgres?imgurl=http://www.carolina.com/images/en_US//local/products/detail/700101_d_bit.jpg&imgrefurl=http://www.carolina.com/product/carolina%26%2523153-%2Baborh%2Btyping%2Bsynthetic%2Bblood%2Bkit.do%3Fkeyword%3Dsynthetic%2Bblood%26sortby%3DbestMatches&usg=__pmJz-uqjs79AW75n9mBmn4lLPBI=&h=250&w=250&sz=7&hl=en&start=109&um=1&tbnid=AKkRa7bQSrXspM:&tbnh=111&tbnw=111&prev=/images%3Fq%3Dblood%2Btyping%26ndsp%3D20%26hl%3Den%26safe%3Dactive%26sa%3DN%26start%3D100%26um%3D1 (pic)
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