Unit 7: Questioned Documents and Chromatography. 1. Class characteristic—ink analysis, paper...

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FORENSIC SCIENCE

Unit 7: Questioned Documents and Chromatography

EVIDENCE 1. Class characteristic—ink analysis,

paper analysis, most handwriting analysis

2. Individual characteristic--With document analysis, it is difficult to identify to an individual characteristic except with typewriter or printer specific marks.

QUESTIONED DOCUMENTS Involves the examination of handwriting, ink, paper, etc. to

ascertain the source or authenticity or detect any changes.

Examples include letters, checks, licenses, contracts, wills, passports, suicide notes, receipts, etc.

Topics

Handwriting analysis

Ink (and pens)

Paper (and pencils)

Forgery

Codes and Ciphers

QUESTIONED DOCUMENTS Forensic Document Examiner--involves

the analysis and comparison of questioned documents with known material (exemplar) in order to identify whenever possible, the author or origin of the questioned document.Unfortunately, no federal licensing exists. May also be asked to determine if changes

have been made. Graphologist--attempts to predict

character traits (personality) from handwriting examination

HISTORY Led to the conviction (and execution) of

Bruno Hauptmann in 1930 based on ransom note handwriting.

Has not always been accepted by the courts.

In 1999, the US Court of Appeals determined that handwriting analysis qualifies as “expert testimony” and is admissible provided it follows scientific guidelines.

HANDWRITING Everyone has a unique handwriting style

despite variations that occur due to mood, age, and hurriedness.

Handwriting analysis involves two phases:The hardware--ink, paper, pens, pencils,

typewriter, printersVisual examination

Most frequently requested type of document analysis

There are 12 characteristics that are commonly examined. (RM pages 33-35)

LINE QUALITY Line quality—do the letter flow or are

they deliberate

SPACING Spacing of words or letters—what is the

average space

SIZE CONSISTENCY Ratio of height, width, and size of the

letters—are they consistent

CONTINUOUS Lifting pen—does the author lift his pen

between words

CONNECTING LETTERS Connecting strokes—how are capital

letters connected to lowercase letters

LINE HABITS Strokes to begin and end—where do

they letters begin and end on the page

PEN PRESSURE Pen pressure—how much pressure is

applied on the up and down stroke

SLANT Slant—do the letters slant left or right or

variable

LETTERS COMPLETE Are letters completely formed?

CURSIVE OR PRINTED Are letters cursive, printed, or both

FANCY CURLS OR LOOPS Fancy writing habits—unusual loops or

curls; unique styles

DIACRITICS Placement of diacritics—crossing t’s and

dotting i’s

HANDWRITING ANALYSIS

Goal is to detect forgeries (documents made, adapted, or falsified in an attempt to deceive someone)

“ACE”

Analysis of the “knowns” with a determination of the characteristics found in the known . Exemplars (letters, diaries, cards, personal notes)

Analysis of the questioned or unknown writing and determination of its characteristics

Comparison of the questioned writing with the known writing.

Evaluation of the evidence, including the similarities and dissimilarities between the “questioned” and “known” writing.

OBTAINING HANDWRITING SAMPLES

The subject should not be shown the questioned document.

The subject is not told how to spell words or use punctuation.

The subject should use materials similar to those of the document.

The dictated text should match some parts of the document.

The subject should be asked to sign the text. Always have a witness. Repeat with the non-writing hand. Samples should be both requested and collected.

BIOMETRIC SIGNATURE PADS Recognizes your signature based on

speed, pressure, and rhythm of signing. Slight differences can be detected.

FISH Forensic Information System for

Handwriting Database for handwriting used and

maintained by the Secret Service. Eliminates subjective opinions. Has been used to verify that no two

individuals pen their words exactly the same way.

SHORTCOMINGS Standards aren’t always good.

Sometimes the standard for comparison is a forgery as well.

Effects of mood, age, drugs, fatigue, and illness on handwriting aren’t always predictable.

LINGUIST Experts that look at the linguistic

content (the way something is written) of a questioned document.

Language that is used can help to establish the writer’s age, gender, ethnicity, level of education, professional training, and ideology.

FORGERY OR FRAUD A forgery is the act of falsifying

something with the intent to deceive someone.

Fraud is committed when you profit (some material gain) from a forgery.

CHECK FORGERY Checks can be forged by:

Ordering someone else’s checksDirectly altering a check Intercepting someone’s check, altering it,

and cashing it.Creating forged checks from scratch

CHECK FORGERY Ways to prevent

Checks printed on chemically sensitive paper

Use large font sizeHigh resolution borders that are hard to

copyPrint in multiple color patternsEnhanced fibers that glow under different

lightsUse chemical washes that change colors when a check is altered.

INK Chromatography--physically separate

mixtures of gases, liquids or dissolved solids.

TypesGas ChromatographyHPLC--high-performance liquid

chromatographyTLC--thin-layer chromatographyPaper Chromatography

Gas ChromatographyUsed to determine the chemical composition of unknown substances, such as the different compounds in gasoline shown by each separate peak in the graph below.

Paper ChromatographyCan be used to separate the components of inks, dyes, plant compounds (chlorophyll), make-up, and many other substances

Liquid ChromatographyUsed to identify unknown plant pigments & other compounds.

Thin-Layer ChromatographyUses thin plastic or glass trays to identify the composition of pigments, chemicals, and other unknown substances.

Examples of Chromatography

PAPER CHROMATOGRAPHY WITH INK Two samples of black ink from two

different manufacturers run using paper chromatography.

RETENTION FACTOR

This is a number that represents how far a compound travels in a particular solvent

It is determined by measuring the distance the compound traveled and dividing it by the distance the solvent traveled.

RETENTION FACTOR

BLACK MARKER AFTER CHROMATOGRAPHY

GAS CHROMATOGRAPH Separates mixtures The written record of the results is

called a chromatogram. A typical one will show a series of peaks,

with each representing one component of the mixture.

This allows identification of class characteristics.

MASS SPECTROMETER an instrument that connects to the gas

chromatograph. The substance is exposed to a beam of

high-energy electrons. Fragments then pass through an

electronic or magnetic field where they are separated according to their masses.

No two substances produce the same fragmentation pattern, thus producing individual characteristics.

PAPER

Weight

Color

Water marks

Age (binding agents and chemical composition)

PENCILS

Lead Hardness Scale--a traditional measure of

the hardness of the "leads" (actually made of graphite) in pencils. The hardness scale, from softer to harder, takes the form ..., 3B, 2B, B, HB, F, H, 2H, 3H, 4H, ..., with the standard "number 2" pencil being of hardness 2H.

COUNTERFEITING When documents are copied with the

intent to deceive. The most common are traveler’s checks,

bonds, and currency. Counterfeiting on money is investigated

by the Secret Service.

COUNTERFEITING PREVENTION US currency has specific features to

make it difficult to counterfeit. The number one feature is the special

paper it is printed on. Counterfeit detection markers contain

iodine which reacts with fake money to turn blue-black. Claim to be 98% effective.

1. portrait stands out and appears raised 2. there is micro printing on the security

threads and portrait. 3. serial number is evenly spaced and

same color as treasury seal 4. check letter and quadrant number

5 and 6 Treasury and Federal reserve seals are sharp and crisp.

7. Red and blue fibers throughout and security thread.

8. federal reserve number and letter

9. series 10. check letter and face plate number 11. watermark on right side 12.Colorshift from copper to green. 13. Clear background lines and detail 14. clear distinct border edge

CODES AND CIPHERS

Codes--letter combinations or symbols used to represent words or concepts

Interception from terrorists and other war enemies

Ciphers--a message in which letters or symbols replace the actual letters in the message.

CODE BREAKING TERMS Encipher (to encode)---to hide the

message; top to bottom in a cipher key

Decipher (to decode)---to reveal the message; bottom to top in a cipher key

SHIFT CIPHER Simplest type of cipher. Works by shifting the alphabet a certain

number of places There are 25 possible keys.

CAESAR SHIFT Caesar simply replaced each letter in a

message with the letter that is three places further down the alphabet.

FREQUENCY ANALYSIS If you have got a message you want to

crack, you can use frequency analysis. In other words, if the sender has tried to

disguise a letter by replacing with a different letter, you can still recognize the original letter because the frequency characteristics of the original letter will be passed on to the new letters.

Which letters are the most common in English?

FREQUENCY ANALYSIS

FREQUENCY ANALYSIS These frequencies are averages, and E

will not always constitute 12.7 % of all the letters in a text, and may not even be the most common letter.

The longer the message, the more likely it is that will obey the average distribution shown above. However, there are exceptions to this rule.

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