Intro to Forensic science-lecture notes- week 23- questioned documents PDF

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Forensic science- lecture notes- week 23questioned documents. Examinations        

Handwriting Signatures Type writing Printing Alterations Indented impressions Paper and ink analysis Damaged documents

What is a questioned document?  

one in which a document in its entirety or in part, is subject to question as to authenticity and/or origin. Anyo Signature o Handwriting o Type writing o Or other marks whose source or authenticity is in dispute or doubtful

Document analysis 

Document examination is a from of forensic science that includes the analysis of handwriting as well as the detection of forged documents such as passports.

Forensic document examiner        

Is the signature genuine? Is the document forged? If so by a particular person? Is the same person the author of several documents? Did someone guide a person’s hand as a will was signed? Did the doctor come back and alter medical records? Did the signer of the document also initial the changes? What is written under the crossed out portion of writing? Was the document written on the date indicated?

What we cant do    

Absolutely date inks Determines a person’s character from their writing Determine gender Identify handwriting that is grossly disguised

Usefulness of comparisons  

No 2 individuals have identical handwriting By adulthood it is exclusive to the individual- we all learned the same techniques to begin.

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Even disguised handwriting will exhibit some of the persons individual characteritistics

Other possibilities      

Rubber stamps/stamp marks Fax rolls Carbon paper/carbonless paper Sequencing Opening/resealing Dry transfer lettering

Most commonly encountered questioned documents          

Letters cheques Drivers licences Contracts Wills Voter registration Passports Petitions Threatening letters Suicide notes Lottery tickets

What type of cases?                  

Forgery Counterfeiting Mail fraud Kidnapping Scams Embezzlement Gambling Organised crime White collar crime Art crimes Thef Robbery Arson Burgulary Homicide Serial murder Psychological profiling Deviant sex crimes

Questioned document history    

Turn of century- lifestyles changed from rural to urban More opportunity for education Advances in ink More paper society

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Exchange of money and handshake it became the exchange of money and signature Need for people to distinguish authenticity of a document Law enforcement would look towards the pen man for help They testified that they could tell the difference in handwriting Accepted in court as they used scientific methods

Types of examinations        

Handwriting comparisons Ink examinations Indented writing Alterations Paper analysis Photocopy analysis Typewriting And other

Handwriting             

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Examination Construction Proportion Slope Handwriting mainly taught at school Personal writing habits Habits remain relatively constant Varies withing a range No 2 people write exactly alike Compare like with like- cannot compare upper case with lower case Cannot compare block writing with cursive or joined writing Compare questioned writing with known writing Ways of getting known sampleso Asking suspects to write samples o Dictate tests o Collect course of business writings such as diaries o Letters, cards Photocopies can be used, but not as good as the real thing. Examination is detailed using a microscope- we need to see how the letters were constructed- which way the pen moved. Slope- for each letter we establish a range of variation. If an example falls outside the range we have established, then it is recorded as a difference. It is hard to establish a range with only one example of a letter- this is why we need large samples. There are 26 letters and 9 numbers- and the examiner can double the 26 comparison to lower case as well.

Examination of handwriting- key factors  

The construction of character forms Many characters can be written in several distinct forms e.g K, E, G, H

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All people exhibit natural variation in handwriting- need sufficient sample available to determine this range. Handwriting changes with age- pronounced in adolescent years and old age Other factors- e.g stress, sickness. The construction of character forms o Striations which follow the direction of curves and in addition deposit ink afer a change in direction. o Definite spots of ink ofen indicate the beginning of a stroke o Thinning at the end of a stroke where pressure is reduced and pen leaves the surface.

Examination of handwriting summary    

Presence of differences is more significant than similarities Structure, shape, proportion and method of formation are all factors in the analysis Must consider natural and other forms of uncontrolled variation Not yet an exact science

Signatures and handwriting        

Style and size Letter designs Letter shapes Letter proportions Spacing Fluency Ratios Positioning

Handwriting-evidential weight 

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Range of concusions o Conclusive o Very strong support o Strong support o Moderate support o Inconclusive That the writer of the known writing did not write the questioned writing

Forensic document examiner     

Are there erasures? Are there alterations or obliterations? What was originally written? Are there perforations, folds, staple holes, or other physical clues on the document? Was the entire document rewritten or was it prepared sequentially, over a period of time?

Handwriting opinion terminology  

Identification – definite conclusion Strong probability- highly probable, persuasive, yet some critical feature

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Probable- points rather strongly to questioned document Indications- evidence to suggest No conclusion- totally inconclusive Indications did not- very weak opinion Probably did not- evidence points strongly against Strong probability did not- highly probable did not Elimination- definite conclusion of identity

Forging signatures   

The forgers dilemma- accuracy vs fluency If go for speed it wont look very like the original If they go slower they will leave hesitations and wobbles

Standard comparisons  

Include sample to be analysed, called an exemplar Samples from an individual includeo Collected writing comes from prior to the beginning of the investigation- helps prevent or indicate when a person is disguising their handwriting o Requested writing is a dictated texted using the same type of paper o Same type of ink as the sample to be analysed.

Digital technology 

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Photocopiers, fax machines and computer printers an examiner may be called on to identify to make and model of a machine or to compare a questioned document with test samples from a suspect machine. Side by side comparison is made Examiners compareo Transitory defect marks o Fax machine headers o Toner o Toner application methods o Mechanical and printing characteristics

Inks and printers   

Typewriters were more individual than todays jet ink and laser printers. Difficult to distinguish between models of the same type of laser printer. Dot matrix printers have slightly more individual characteristics than laser and ink-jet devices but becoming obsolete

Typewriters    

Linking typewriters to documents Linking together documents Relatively dating documents Identifying how a document has been produced

Typewriters and printing devices   

Whether the make and model of the device used to prepare the questioned document can be identified Whether a particular suspect device can be identified as having prepared the document In order to do this, individual character’s styles, shape, and size are compared to a complete reference collection of past and present typeface.

Modern office tech        

Identification of the printer/photocopier Linking documents Examination of fraudulent documents Identify how documents were produced, and tie them to an individual machine Ink jet printers- by defects in ink mechanisms Laster jet printers- defects in drum Photocopies-defects on drum We make use of faults in the operation of the machine

Alterations        

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Entries chemically erased Entries physically erased Correction fluid Additions using different pens Photocopying and masking techniques Page substitution Manipulation using computers Technology o VSC o Laser o Microscope ELSA Destructive tech o TLC

Printing forgeries  

Use of commercial or industrial printing processes produce high value forged documents A document examiner would compare the print quality

Indented impressions  

Invisible marks lef on paper by writings on other pieces of paper. Oblique lighting

Other analytical tests Instruments used in QD lab   

Stereo microscope Light microscope Visual spectrum comparator

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Electrostatic document apparatus

Equipment used in document analysis    

Electrostatic detection apparatus Video spectral comparator TLC Infrared reflectance

Indented impressions techniques  

Oblique light ESDA

Types of non-destructive testing      

Measuring handwriting and type writing Magnifiers Light box Photos ESDA VSC

Ink and paper comparisons   

Chemical composition of ink used on documents Visible-light microspectrophotometer TLC

Examination of inks  

Been altered? Different inks Illuminated with non-visible radiation or excited by fluoresces

Ink analysis 

Chemical tests o Ink solubility o Paper chromatography o TLC

Infrared reflectance  

Show residue of pencil marks- even if erased Graphite= carbon= absorbs infrared light

ESDA   

Document laid on device, cover with plastic film and induce electric charge Impressions can be developed with black powder and recorded with adhesive sheet Non destructive and reliable

Video spectral comparator 

Light source for document examinations and verification of official documents

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Used to analyse inks- under different light conditions where some wavelengths are blocked. Can uncover layers in documents where words have been scribbled out or written over.

Damaged documents    

Re assembling Shredded Fire damage Moist

Alterations  

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Alterations o Different ink detections Erasures o Rubber o Sandpaper o Razor blade, or knife Obliterations o Overwriting o Crossing out o Hide the original writing can be revealed by infrared radiation.

Collecting samples or exemplars     

Adequate number Known writing- should contain some of the words and combination of letters present in questioned document Implement and paper should be alike Dictation of several pages Exemplar- handwriting used as a standard for comparison o Dictated or requested o Un-dictated or collected...