Unit 7: Questioned Documents and Chromatography

Transcription

1 Unit 7: Questioned Documents and Chromatography

2 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.

3 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

4 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

5 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.

6 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.

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8 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, printers Visual examination Most frequently requested type of document analysis There are 12 characteristics that are commonly examined. (RM pages 33-35)

9 Line quality do the letter flow or are they deliberate

10 Spacing of words or letters what is the average space

11 Ratio of height, width, and size of the letters are they consistent

12 Lifting pen does the author lift his pen between words

13 Connecting strokes how are capital letters connected to lowercase letters

14 Strokes to begin and end where do they letters begin and end on the page

15 Pen pressure how much pressure is applied on the up and down stroke

16 Slant do the letters slant left or right or variable

17 Are letters completely formed?

18 Are letters cursive, printed, or both

19 Fancy writing habits unusual loops or curls; unique styles

20 Placement of diacritics crossing t s and dotting i s

21 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.

22 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.

23 Recognizes your signature based on speed, pressure, and rhythm of signing. Slight differences can be detected.

24 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.

25 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.

26 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.

27 Checks can be forged by: Ordering someone else s checks Directly altering a check Intercepting someone s check, altering it, and cashing it. Creating forged checks from scratch

28 Ways to prevent Checks printed on chemically sensitive paper Use large font size High resolution borders that are hard to copy Print in multiple color patterns Enhanced fibers that glow under different lights Use chemical washes that change colors when a check is altered.

29 Chromatography--physically separate mixtures of gases, liquids or dissolved solids. Types Gas Chromatography HPLC--high-performance liquid chromatography TLC--thin-layer chromatography Paper Chromatography

30 Examples of Chromatography Liquid Chromatography Used to identify unknown plant pigments & other compounds. Thin-Layer Chromatography Uses thin plastic or glass trays to identify the composition of pigments, chemicals, and other unknown substances. Gas Chromatography Used 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 Chromatography Can be used to separate the components of inks, dyes, plant compounds (chlorophyll), make-up, and many other substances

31 Two samples of black ink from two different manufacturers run using paper chromatography.

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33 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.

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36 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.

37 an instrument that connects to the gas chromatograph. The substance is exposed to a beam of highenergy 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.

38 Weight Color Water marks Age (binding agents and chemical composition)

39 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.

40 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.

41 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 blueblack. Claim to be 98% effective.

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44 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

45 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

46 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

47 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.

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49 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

50 Simplest type of cipher. Works by shifting the alphabet a certain number of places There are 25 possible keys.

51 Caesar simply replaced each letter in a message with the letter that is three places further down the alphabet.

52 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?

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54 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.